Methods: algae control or growing plants?

Tom Barr

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Since GSA grows mostly on glass, rarely on plants, it would be more accurate I would think to assume it was a mix of CO2 and PO4 that prevents new germination of the GSA spores.

Competition has nothing to do with it.
This is rather obvious in terms of PO4, NO3 etc..........or light..........but............not CO2 very often.
Light and nutrients are easy to simply add excess non limiting resources.........this is a control for resource competition.

Many aquarist seem to have poor abilities to do the basics of competition studies for aquatic plants, but this is VERY basic logic in plant ecology and applies to algae as well.
We can verify the light and nutrients easily.

CO2 is much moire troublesome for most planted hobbyist.
Much harder to really verify, but..........you have 2 of the 3 main things, so take care of those, then focus on CO2 thereafter.
Use algae and good plant health as the test kit to slowly add more CO2.

CO2 is the most limiting nutrient for plants, and virtually never limiting for algae.
So it is really about hurting your plants and their growth, not algae, they just respond to poor plant health when there are plants present.
Nutrients/light otherwise when there are no plants.

Regards,
Tom Barr
 

Tug

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Just looking at this myself and I'm finding non-limiting, PO4 stability helps. Say PO4 stability was the sign of a balanced something else, CO2. That might keep the algae from reacting. Drops or swings might suggest a distressed environment to some algae (GSA) and crap, it's just what their into. I get some I clean off, once a month generally. I run a yeast CO2 generator, so CO2 is likely involved. Anyway, when is it not?

I can't read my PO4, my test is in the trash can.
But, I dose ~7ppm/week+high amounts of PO4 from their food, etc.
Really, I don't spend a lot of time cleaning glass.
 
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Tug

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Start dosing less then EI. And, things get even more limiting.

:gw I see more GSA trying to limit (lower my EI dose after testing something) phosphate.
 
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darkoon

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thanks for the replies. I will try to increase PO4 level to >5 first, if that doesn't work, I will try to slowly increase CO2.
btw, the gsa i got in my tank grows on the old leaves of the plants too. now, could that have anything to do with excessive ambient light I have in the living room? my living room is lit up 7ish in the morning, and lights out 10ish at night. the tank lights on at 11, off at 7pm.
 

Yo-han

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Read this thread with great interest. Always wondered why PO4 limitation worked for some people while others had no algae with high PO4.

But this whole story raises a new question: If everything is non limiting (nutrients, CO2) and you only use light to limit growth, than for algae there is a non limiting environment as well. Than what is limiting algae growth? It isn't CO2 or nutrients and in a normal tank there would be enough light for algae to grow.

So the only thing I could came up with is that plants leach some kind of hormone or chemical into the water that inhibit algae from growing. If so, why don't they sell this in a bottle? If not, how is it possible that algae don't grow in a non limiting environment?

Regards,
Johan
 

Tom Barr

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Yo-han;64195 said:
Read this thread with great interest. Always wondered why PO4 limitation worked for some people while others had no algae with high PO4.

Simple, PO4 limitation can become stronger than CO2 limitation when you add say 15-30ppm of CO2 and then try to keep about 0.1-0.2ppm of PO4.
If you add 4 ppm of PO4, then the CO2 demand is more limiting.

This is the very basic tenent regarding Liebig's law of the limitation.

Since many did not realize that CO2 is also a limiting factor, and it's very poorly measured as well........they assumed it was limiting PO4 that was the key.
I falsified this hypothesis along with Steve Dixon.

So it CANNOT be due solely to PO4 "excess"(let's say 5ppm of PO4).
There has to be some other factor, it cannot possibly be PO4 independent of other factors.

There is simply no way that can possibly be true.

It does not say why other folks have algae etc.......only what it cannot be due to.
Other folks can replicate this and add good CO2, lower light etc.......and have no issues with algae.

But this whole story raises a new question: If everything is non limiting (nutrients, CO2) and you only use light to limit growth, than for algae there is a non limiting environment as well.

Why do you assume that algae that has a very very different life cycle in our aquariums is anything remotely like clonally reproduced plants?
There is no aquarium with a tank full of plants that is limiting to algae, this also goes for CO2 as well.
Many species of algae can grow at even less PAR light than most plants.

"What causes the algae spores to germinate or move from one life historty stage to the other?" is a much better question.

There are signals, not absolute concentrations that tell a specific alga when it a good time to germinate.
Maybe it's just variation in CO2, or O2, perhaps some bacteria in the root zone or NH4 spike, or a clogged filter, a drop off or reduced water flow, soem singal that the plants are now doing poorly and it's a good time to grow and complete their life cycle.

Plants? They just grow, we do not flower and raise them from seeds etc.

Than what is limiting algae growth? It isn't CO2 or nutrients and in a normal tank there would be enough light for algae to grow.

Seems they can tell when "someone else is there".
So can plants, they can tell the difference between a rock blocking their light and another plant or even their own leaves. Perhaps algae spores can detect a % of leaves or other algae absorbing certain wavelengths and reflecting mostly green light.
Since plants can tell if it's a leaf vs say a piece of wood, there's no reason why algae cannot as well.

I'm not aware of any real test done with respect to two groups, but it would be of interest.

So the only thing I could came up with is that plants leach some kind of hormone or chemical into the water that inhibit algae from growing. If so, why don't they sell this in a bottle? If not, how is it possible that algae don't grow in a non limiting environment?

Regards,
Johan

Many have loved this idea, and it does not work.
Many researchers have looked for allelopathic chemicals and it has never been shown in natural systems.
The controls and the test are very tough, it's not that the concepot etc is hard, but the controls have really caused some people to make bad conclusions and assumptions.

I think light and CO2 play larger factors with good reason, they are more pervasive and indicative of when someone else is there and in high enough biomass to cause problems. CO2 variation is good since it suggesta die off, or a change, or a lot of run off into a lake or stream. Same for light there as well.

Aquatic plants and algae compete mostly with respect to light, not much else.
 

nipat

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Tom Barr;64218 said:
Simple, PO4 limitation can become stronger than CO2 limitation when you add say 15-30ppm of CO2 and then try to keep about 0.1-0.2ppm of PO4.
If you add 4 ppm of PO4, then the CO2 demand is more limiting.---

I've been wondering about these for a while now but was afraid to ask.

From the sentences above, it can be interpreted that PO4 limiting doesn't cause algae but CO2 limiting does?

This baffles me. Because by your explanation about PMDD, I interpret that plants grow well even if CO2 is not optimum because they are PO4 limited. And when PO4 is added, algae grows because plants condition gets worse from CO2 limiting.

It sounds conflicting to me. Because how can plants be in better shape with PO4 limiting + not optimum CO2 (that is two limiting factors) than with PO4 non-limited at the same level of CO2 (only one limiting factor)?

And if so, then it sounds like we can be relaxed about CO2 level whenever PO4 is limited? And then isn't that an easier way to grow aquatic plants without algae and safer for critter too (from lower CO2 level)?

In my previous tank, I had 2 moments when it looked best. The first moment was when doing EI. Then I tore it down and restarted, this time I had to limit PO4 to control algae and that was the second moment when it looked best. Still don't know why.
 

Tom Barr

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No, PO4 limits the plants and the CO2 limits the plants, the MOST limiting factor can shift from one to the other..........this is the Law of the Minimum that Liebig suggested and has since been made from a hypothesis, to a theory to a law of nature.
It's pretty hard core when it's a Law.

There is no conflict at all.

Aquarist might be confused because they are associating poor growth due to poor CO2 limitation to that of algae blooms.
These are two different issues.

Plant growth is where this all starts.
Plants have many ways to cope with PO4 limitation, they have far few ways to deal with large changes in CO2 concentration.

So the plants still grow okay with a moderate PO4 limitation, say reduced growth by say 20%.
If the PO4 is non limiting suddenly, then the CO2 limitation is more pronounced......more serious and much more detrimental to the overall metabolism of the plant.
This shuts everything down.

There are far more expensive enzymes associated with carbon metabolism than a decline in PO4.
The plants who can respond well to changes in CO2 are the weedy species, Egeria, Hydrilla, pondweeds, Vals and a few others.

Most species we keep cannot however.

So when the plants shut downs..........the algae appear.
If you strongly limit PO4, then you will get algae as well because that can shut a plant down as well if the limitation is strong enough, but CO2 metabolism is much more sensitive due to the amount of enzymes and the central role to all other functions.

PO4, ALL the plants have ways around this if the limitation is mild/moderate.

PMDD suggested moderate limitation, not strong limitation for PO4, many folks misread what Paul suggested.
He never once suggested absent or anything of the like for PO4, rather, 0.1ppm to maybe 0.2ppm.

If you look at this graph, which is an easier target to hit/add? At the B range or the D/C range?

Why bother with CO2 or PO4?
CO2 is only toxic if you lack O2, poor current etc, poor control/dosing of it, bad shoddy equipment, basically bad care with usage and/or way too much light for the demand it will create.

You should have a nice wide effective range that allows plenty of CO2 for plants without any STRESS for the fish.
If this is a narrow edge, then something else should be addressed, most likely O2/current etc..........cleaning the filters more often etc........too much light and what not.

Same for having to limit PO4.

Micro_Growth_Curve_Use.jpg


Problem is with limiting PO4=> you get nasty GSA. It's not all peach and cream. Also, if you start with a general philosophy about what is best for management and fish health....you know it should start with light intensity, then progress to CO2.....and so on down the line....not start with PO4.
It works, but it is the tail wagging the dog and waste the light, the CO2 etc. It is also tougher to manage and test for than say light if you can get a PAR meter for a few minutes one time.

Anytime you have a limitation other than lighting, you are wasting light.
CO2, nutrients are very cheap relative to electrical energy.
 

Yo-han

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Tom Barr;64218 said:
Many have loved this idea, and it does not work.
Many researchers have looked for allelopathic chemicals and it has never been shown in natural systems.
The controls and the test are very tough, it's not that the concepot etc is hard, but the controls have really caused some people to make bad conclusions and assumptions.

I think light and CO2 play larger factors with good reason, they are more pervasive and indicative of when someone else is there and in high enough biomass to cause problems. CO2 variation is good since it suggesta die off, or a change, or a lot of run off into a lake or stream. Same for light there as well.

Aquatic plants and algae compete mostly with respect to light, not much else.

Before I read your answer I was looking for scientific articles about allelopathic chemicals and found out, ada does sell it. Phyto-Git, containing phytoncides. Allthough this is probably mainly a commercial product, at least I was not the only one thinking about it.

Also I found an article about phytoncides killing microbes. The microbes they where looking at where mainly bacteria (which we don't want to kill in our aquarium) but there are many phytoncides, so perhaps there are more algae specific phytoncides as well. Would be a real moneymaker!!

Thinking about allelopathic chemicals in our aquarium; than a waterchange would only have a negative effect, because you wash them away (unless tapwater contains phytoncides as well). So it is not very likely that phytoncides are responsible for our nice algaefree tanks. But perhaps it would be a nice suplement.
 
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Tom Barr

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nipat;64248 said:
Thanks Tom. It's clear now. :)

Let me follow up a bit more here.
This is NOT about algae, it never was..........

It's about the rate of plant growth.

The problem is that we have trouble as humans supplying the right amounts of light, CO2 and nutrients to balance the plant's needs.

No other short cut is really going to make you a better horticulturalist, you need to master light and CO2 first.
Then folks toss in the algae issue, which is indirect consequence of poor plant growth, poor horticulture, it has nothing to do with nutrients or competition.

This is a huge chasm in the philosophical difference between the algae killers and the focus on growing plants.
Limiting PO4 is reactionary because the aquarist has never mastered CO2 well. PO4 is a crutch in otherwords to avoid facing the reality of one's own limitations. Ouch.

Some like to suggest it's an alternative and it is, but a very poor one that does not lead to better plant growth and horticulture, it only limits plant growth and makes CO2 & light usage less efficent. If you need to slow things down, use less light. Or go non CO2 etc. It is also hard to manage and suggest PMDD for other folks trying to replicate those same conditions. EI rapidly replaced PMDD for this simple reason if for no other. We also do not learn much biologically about the plants in using the PMDD approach either, nor much about the algae for that matter. There is ample Science on light and CO2 effects on the rates of growth, same for algae, nutrients are harder to dicipher.

So this is about growth and teaching folks what plants need and how best to manage growth, not about algae.
Algae is indirect and rarely ever an issue once you realize it's all about the plant growth.

If it is........then we need to go back and look at the CO2/light mostly, nutrients? They are easy to add enough of and move on to the next step.
I think many give CO2 a free pass, and this is a very bad assumption, they need to learn about CO2 more than perhaps any single variable.
 

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Yo-han;64252 said:
Before I read your answer I was looking for scientific articles about allelopathic chemicals and found out, ada does sell it. Phyto-Git, containing phytoncides. Allthough this is probably mainly a commercial product, at least I was not the only one thinking about it.

Also I found an article about phytoncides killing microbes. The microbes they where looking at where mainly bacteria (which we don't want to kill in our aquarium) but there are many phytoncides, so perhaps there are more algae specific phytoncides as well. Would be a real moneymaker!!

Thinking about allelopathic chemicals in our aquarium; than a waterchange would only have a negative effect, because you wash them away (unless tapwater contains phytoncides as well). So it is not very likely that phytoncides are responsible for our nice algaefree tanks. But perhaps it would be a nice suplement.

"Phytocide", this term is "Steer manure speak" and something them holistic crazy talk people put out.
Phyto means plant, so it kills plants?
WTF?

If you sell something, be specific, sell an algicide. Perhaps they labeled it with this mumbo jumbo terms made to make you feel all warm and furry? Or to aviod correct labeling for the specific intended purpose?
Either way, it's BS.

There's many plant products that can be crushed up and kill things, say like hemlock and Socrates:)
Does not mean hemlock is going to kill humans that live near it.

Excel/glutaraldehyde kills algae and can be broken down by green algae and plants as a carbon source.
Peroxide can do the same things as Phytogit as well.

Of course Amano does not sell H2O2 and the drug store label on the bottle does not have a little plant on it and some poetry.
But it does indeed work and kills algae when used correctly.

Your rational about water changes is fairly reasonable. They should illict a positive algae response, eg more growth, biomass of algae.
No one to date has even remotely shown this to be the case. In fact, the reverse has been shown. Another control to test this hypothesis is to simply add Actived carbon, which removes large organic compounds like...........allelopathic suspects:)
This control can be applied to non CO2 and CO2 enriched planted tanks with the same effects as a water change, things get better, not worse.

No one wants to debate me on this topic because they do not want to test the hypothesis, or set up a reasonable method and control to investigate, instead, they wanna sell their snake oil and bicker and go with what they want to believe rather than facing the music and looking at the evidence. It's a serach for an agenda, not truth.

It's like "I believe in Stana Claus" debate.
Hummm....maybe we need a Truth Fairy?
 

jonny_ftm

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What I personally noticed, many times, is that with no WC, in an EI tank, algae comes quickely after 3-4 weeks. Even a trial of decreasing ferts won't help.

Also, I often noticed that when there's an algae problem, it is rarely an only one-cause issue. Often, once algae are present, you end up adjusting many small parameters (light, ferts...). Once an algae bloom occurs, I find it even more important to review every step, as with time we could get loose on some steps, even after years of expierience.

One problem is that it takes 2-3 weeks to see a significant response after a given change in a parameter, so most people won't wait enough while seeing alage killing their biomass.

An other thing I often noticed, when there's an algae bloom, they grow everywhere, but in a more pronounced manner over organic debris. Hard to say what triggers what, as growing alage will kill plants and cause more debris, which will even give more fuel to the algae.

In a stable aquarium, organic debris will rarely cause issues, unless the tank is really badly maintained. But, in a tank with a severe algae bloom, I find that a severe trimming of plants, a deep cleaning of organing debris, coupled with lowering of light and good CO2/EI, will give you the quickest results, in 2-3 weeks problem is often solved. Spirogyra often comes at that point, when healthy plants are growing back. I only remove it from time to time. When plants are enough established, it goes dormant. If not, light should be decreased in my expierience.

Finally, I'm recently discovering the virtue of Ramshorn snails. Like most invertebrae, they are very efficient energy based organism: they consume more than they pollute. Their advantage over most critters and snails are a big size, a robust appetite coupled to a good speed and ability to swim in free water or stay at water surface to remove any debris. Main disadvantage is the high number needed for a slow growing tank. I can't imagine the mass in a high growing tank. Hopefully, they breed like crazy.

EI, for me, makes really life simpler, I no longer buy test kits (except GH when I change house), I even dropped my dropchecker since 3 months now. Spared so much money since then. I also spared a lot of money because I buy much less plants. Even after terrible algae blooms, we can get always plants to rebirth from their roots, when offered good conditions.
 

Yo-han

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Tom Barr;64259 said:
No one wants to debate me on this topic because they do not want to test the hypothesis, or set up a reasonable method and control to investigate, instead, they wanna sell their snake oil and bicker and go with what they want to believe rather than facing the music and looking at the evidence. It's a serach for an agenda, not truth.

It's like "I believe in Stana Claus" debate.
Hummm....maybe we need a Truth Fairy?

I would love to see this subject debated more, because I dont have the material to test it. I'm a pharmacist/toxicologist, so quite familiair with chemistry but not with plant (read: algae) biology. I can imagine what happens during a water change, and it would not be benificial for the hypothesis: allelochemicals reduce/kill algae.

jonny_ftm;64300 said:
One problem is that it takes 2-3 weeks to see a significant response after a given change in a parameter, so most people won't wait enough while seeing alage killing their biomass.

The main reason why I thought of a signaling chemical is the fact that it always takes a few weeks before the algae disappear. How do you explain that?

So I've a hard time accepting the statement that CO2 functions as the chemical responsible for letting algae know, when to grow or not to grow. I use pH controlled CO2 injection, so this is quite stable, but still have minor algae outbreaks from time to time (depending on my nutrients dosing habits). Also I assume, algae would respond much faster than a few weeks after stabilizing CO2. I feel (and I can't back this up jet) there is more to it, love to test, but this takes time with only one tank. Tested 40ppm PO4 lately:p now plants are recovering from this shock!

And that is why I (and I guess many others) come to this forum, you're one of the few who tests things scientifically.

As soon as I get my PhD and money to spent, I'll love to do this kind of research as well, till then, I depend on findings of others and my own thoughts to see if that could be right.
 

Tom Barr

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Yo-han;64302 said:
I would love to see this subject debated more, because I dont have the material to test it. I'm a pharmacist/toxicologist, so quite familiair with chemistry but not with plant (read: algae) biology. I can imagine what happens during a water change, and it would not be benificial for the hypothesis: allelochemicals reduce/kill algae.

Yes, but you should know enough to realize that activated carbon will also remove these larger organic chemicals, even the smaller ones.
This can be looked up etc and is in some of the allelopathic methods for controls in a few different studies, at least the better ones, not mere test well assays, which offer little ecological significance but are often touted as some miracle of investigative Science in this hobby.

The main reason why I thought of a signaling chemical is the fact that it always takes a few weeks before the algae disappear. How do you explain that?
So I've a hard time accepting the statement that CO2 functions as the chemical responsible for letting algae know, when to grow or not to grow.

I have little dount that it is several PARAMETERS versus just one. The evidence is poor there but so are the methods to assay and investigate the questions, many different plant species, and the status and health of the plants themselvesa re NOT addressed.

We know healthy strong plants are much more resistent.
Same broadly for all ecologicals systems, strong estbalished systems will resist change vs weak 1/2 dead systems.

CO2 is a good parameter for algae spore sensing since the levels go up almost universally and then decline with runoff into streams, lakes etc.

I use pH controlled CO2 injection, so this is quite stable, but still have minor algae outbreaks from time to time (depending on my nutrients dosing habits). Also I assume, algae would respond much faster than a few weeks after stabilizing CO2. I feel (and I can't back this up jet) there is more to it, love to test, but this takes time with only one tank. Tested 40ppm PO4 lately:p now plants are recovering from this shock!

And that is why I (and I guess many others) come to this forum, you're one of the few who tests things scientifically.

As soon as I get my PhD and money to spent, I'll love to do this kind of research as well, till then, I depend on findings of others and my own thoughts to see if that could be right.

If the pH is the controller, how do KNOW the CO2 is really a certain ppm and how do you KNOW the KH is universally stable and a 100% bicarb?

Without a reference, you really do not and cannot say much. If this was the case and so simple, we'd all use pH controllers.
PO4, tannins and NH4 toss the pH/KH relationship out of whack and we add these to the tank also.
 

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Tom Barr;64303 said:
If the pH is the controller, how do KNOW the CO2 is really a certain ppm and how do you KNOW the KH is universally stable and a 100% bicarb?

I measure KH, and it fluctuates insignificant during the week. Never tested it on different times of the day but I don't expect much change there either. Have two dropcheckers in there as well, for control.
And no, it is not 100% bicarbonate. My pH is 6.4, so that will give me about 50% bicarb and 50% carbonic acid if i'm right. (pKa1 = 6.352 at 25 °C)

Tom Barr;64303 said:
Without a reference, you really do not and cannot say much. If this was the case and so simple, we'd all use pH controllers.
PO4, tannins and NH4 toss the pH/KH relationship out of whack and we add these to the tank also.

The influence of PO4 as a buffer is overrated. I ones calulated that 1ppm PO4 raises KH with 0.015 degree at pH 7.0. Below 7 the influence only gets smaller. I have no NH4 and since using purigen, little tannins. So not much buffer except for carbonates. So quite sure about my CO2 for as far as I can be without using expensive tests.

So that's why I expect CO2 of little influence. Larger allelopathic chemicals that reduce algae as well. But just saying healthy plants are more resistant, can't be true either. Because why do algae grow on glass, wood and rocks only when plants are doing bad...

Just throwing in a new ball I thought of: sugars! Could it be the other way around? Not allelopathic chemicals from healthy plants that reduce algae, but an (lets call it) allelopathic chemical from unhealthy plants that induces algae. First thing on my mind, sugars, but if someone knows anopther good one, just name it.

Read some article about someone who tried to use sugar as carbon source for his plants, ended up with more algae then before. Off course, I don't know whether all other parameters where kept the same, but they use sugar to grow algae for biogas, so there could be a relation there as well.
 

jonny_ftm

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Since I dropped my PH meter, my tank and plants came to life. Now, I even dropped the drop checker. So many people here reported issues when on a PH meter. When they moved to a good misting solution, it solved most issues, even in a more stable manner than complete dissolution.

Tom and others here played with CO2 meters and showed us the high fluctuations in CO2 levels, the non correspondance between CO2/KH/PH in our tanks (those tables were developped for distilled + bic) and even the inaccuracy + response delays of drop checkers.

Also, there's a universally admitted fact: Plant growth will stunt when a given nutrient is deficient.
When plant growth stunts, algae emerges.

Having a good stable CO2 / light balance, let you play only with water column nutrients. If any nutrient in water column lacks totally, it will lead to a plant stunt, just like with CO2.

Having enough nutrients and light, will make CO2 the limiting factor. Either you optimize CO2, or plant growth stops, like with any other nutrient.

CO2, N, P and K are macro nutrients. So, a lack in them will end quicker to a growth issue compared to micro.

Decaying plants produce organics needed by algae, explaining why they bloom everywhere, and not only on decaying plants. Also, healthy plants are known to inhibit algae growth by some sorts of hormones.

Many many variables, but one thing is sure, following EI/CO2 makes you have stunning tanks, stable even after heavy trimming, without even those occasional algae blooms when ever you change a little in your routine.

Flooding nutrients won't cause algae on such tanks. Boosting light or stopping CO2 will do. That's the observational evidence we have
 

Tom Barr

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Yo-han;64304 said:
I measure KH, and it fluctuates insignificant during the week. Never tested it on different times of the day but I don't expect much change there either. Have two dropcheckers in there as well, for control.
And no, it is not 100% bicarbonate. My pH is 6.4, so that will give me about 50% bicarb and 50% carbonic acid if i'm right. (pKa1 = 6.352 at 25 °C)

I've used pure DI water made up with sodium carbonate and flushed a tank, then added CO2 and used the pH/KH........., I've also used known % CO2, N2 gas mixtures(5% and 95%) to answer this.
You mention your pH is 6.4, but you did not mention what the KH was measured at.

What good is that with the other?

The influence of PO4 as a buffer is overrated. I ones calulated that 1ppm PO4 raises KH with 0.015 degree at pH 7.0. Below 7 the influence only gets smaller. I have no NH4 and since using purigen, little tannins. So not much buffer except for carbonates. So quite sure about my CO2 for as far as I can be without using expensive tests.

Tap water also has other non carbonate alkalinity as well, you risk being over confident here. SeaChem makes several so called "buffers" and they can easily toss the chart off by huge factors with fairly small additions.
Some tap water has odd stuff they add or is naturall present that also tosses the charts off. I've measured this stuff when I've gone to give presentations. According to the chart and the Lamott Alk test and the calibrated pH test meter, he should have had 220 ppm of CO2, but there's no way the fish could survive, this was in Ohio.

My own tanks with sierra snow melt and granite water shed, about as good and close to rain water as most can hope for, has enough to mess with the reference standards.
I end up with about an error of 10ppm. not bad really, but the KH does move depending on the time of the year.
I do not test it a few times and think it's okay. A simple way is to take a small sample once every 2-4 weeks and then freeze them.
Say 20mls, does not need to be much.

Then you get a better idea.

There is a lot more you do not KNOW than you do here and it does matter if you rely on a specific ppm for CO2.

I do not rely on a specific ppm for CO2 myself.

I work at it backwards.
I get a system that is stable, then go about looking for possible reasons why.
Then I measure the CO2, and then question how much I can honestly say and know about it.
I do the same for lighting, for nutrients, water column or sediment or both.
Filters etc.

So things are bust, that's good to know as well.
Some and many remain inconclusive........
And that's where it's at today with why algae grows.........

So that's why I expect CO2 of little influence. Larger allelopathic chemicals that reduce algae as well. But just saying healthy plants are more resistant, can't be true either. Because why do algae grow on glass, wood and rocks only when plants are doing bad...

Well recruitment is a separate issue from a bloom/germination. I can germinate seeds, but whether they survive and root well depends on WHERE they start growing.
A leaf is not the best long term place to grow if I had to pick one.
The leaf that is healthy in terms of carbon status will have a thicker cuticle. Some species lack any cuticle, but these species can afford to drop leaves and handle pruning easily.
A thicker cuticle may slough off the upper outer layer as more is produced from below.

If something interupts this, say variation that distrupts carbon metabolism.........then production of cuticular waxes...........long highly reduced carbon chains basically.........the algae have a much better site for attachment.
Non live materials also will recruit differently based on what the surface is like, this is well known and researched.

This is for macrophytic seaweeds, but should apply equally well to microphyte freshwater algae.

http://books.google.com/books?hl=en...sczoBCU2oI6O9b7ceESBlMQFA#v=onepage&q&f=false

Just throwing in a new ball I thought of: sgars! Could it be the other way around? Not allelopathic chemicals from healthy plants that reduce algae, but an (lets call it) allelopathic chemical from unhealthy plants that induces algae. First thing on my mind, sugars, but if someone knows anopther good one, just name it.

Well healthy plants already leach about 10% of their photsynthate as it is.....but it's possible. Recruitment would eb the key to look at on a variety of media and live leaves.
Setting up controls for these test is often very hard. It's a big question that has long been asked in Florida lakes and rivers where the bulk of the FW research into periphyton is done.
They have wide range sof nutrients, and no algae and the same pattern with algae. So algae and nutrients are poorly correlated (R^2 is under 0.13) where plants are present.
Crismann did look at CO2 in a couple of lakes and felt he got somewhere.
Not sure if he pursued it further.

You'd need to measure the O2/CO2 data logging over a season or two, which would be hard. But possible.

Read some article about someone who tried to use sugar as carbon source for his plants, ended up with more algae then before. Off course, I don't know whether all other parameters where kept the same, but they use sugar to grow algae for biogas, so there could be a relation there as well.

That would be Roger Miller, I know him, we had that talk some 10-15 years ago. The idea was bacteria would metabolize the reduced carbon into CO2..........but...........at the expense of O2, so with say 5-7ppm of O2........you'd have to resupply this as fast is it is produced........otherwise is would create a strong O2 sink and consume a lot of O2 for only a little CO2 gain. Not a good idea, it's the same as adding more fish to add more CO2.
That too also induces algae if you keep progressively adding more and more fish and keep the other parameters similar.

Most of my own tanks run in the 40-50ppm range for CO2, and a couple at the 60-80ppm range without any issues to live stock and good breeding from shrimp and fish.
I do not attempt to adjust the CO2 to given ppm, but tailor each tank's need based on the plants and the fish. Whatever the CO2 is, it just is. Then once stabilized and doign well, then I take a sample and critically measure it or use a claibrated meter that I know is not influenced by any KH issues.

In theory, you could make one from the drop checker and use a pH meter to measure the pH change in that small volume, I have a dual chamber with 2 holed rubber stoppes and 1/2" hole for the pH probe for this purpose.
Using hoses I can withdraw a sample, then take my time and wait for the equilibrium to be reached. I can also withdraw a smaple from a very specific location in the aquarium without it degassing. It's a sort of PITA to use it, but it does give good results and it takes day for the ppm' to be read. I'm okay with that. Then I can compare that to the CO2 meter reading at that same time and location. The best I can hope for has been about 1-2ppm +/- in agreement.

I'm still quite fine with the original premise however: healthy plants = healthy fish and little algae.

Sometimes folks spend too much effort and time with the ppm's and not enough watching the tank carefully and responding.
You can be all techy and a lousy horticulturalist. Likewise, some of the betetr scapers I know are lousy techy, but good horticulturalist.
Very few are both.

This is a human issue more so.

Good questions, thank you.
 

Tom Barr

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jonny_ftm;64313 said:
Since I dropped my PH meter, my tank and plants came to life. Now, I even dropped the drop checker. So many people here reported issues when on a PH meter. When they moved to a good misting solution, it solved most issues, even in a more stable manner than complete dissolution.

Tom and others here played with CO2 meters and showed us the high fluctuations in CO2 levels, the non correspondance between CO2/KH/PH in our tanks (those tables were developped for distilled + bic) and even the inaccuracy + response delays of drop checkers.

Also, there's a universally admitted fact: Plant growth will stunt when a given nutrient is deficient.
When plant growth stunts, algae emerges.

Having a good stable CO2 / light balance, let you play only with water column nutrients. If any nutrient in water column lacks totally, it will lead to a plant stunt, just like with CO2.

Having enough nutrients and light, will make CO2 the limiting factor. Either you optimize CO2, or plant growth stops, like with any other nutrient.

CO2, N, P and K are macro nutrients. So, a lack in them will end quicker to a growth issue compared to micro.

Decaying plants produce organics needed by algae, explaining why they bloom everywhere, and not only on decaying plants. Also, healthy plants are known to inhibit algae growth by some sorts of hormones.

Many many variables, but one thing is sure, following EI/CO2 makes you have stunning tanks, stable even after heavy trimming, without even those occasional algae blooms when ever you change a little in your routine.

Flooding nutrients won't cause algae on such tanks. Boosting light or stopping CO2 will do. That's the observational evidence we have

I like that folks use a pH meter with 0.01 accuracy and calibrate them every so often to be really sure versus a drop checker. I really do not like them. I know , I know...many do and swear by them. I still do not like them.

I use pH meters as relative measure and to correlate with say a CO2 meter or a gas chamber device detailed above.
They still can nailed with the KH thing........so I always keep this in the back of my mind and question anything CO2 if something goes astray.

I tried this out a few times, the pH changed some, and it appeared I have more CO2, but the rate was not increased at all. I did not adjust the micrometer handle at all.
Perhaps the plant's uptake/demand for CO2 etc changed?

Hard to say.

I adjusted the CO2 down to match the pH I had prior and then measured the KH. I started seeing reduced growth after 2-3 weeks and some plants just started doign plain poorly. I added more CO2 and ignored the pH, this time I used the micrometer.
This seems wiser to me. pH is still better than the DC's, but that at leats gets around the KH issue, but it poor resolution and slow response.

The gas chamber with the reference KH + a pH probe seems the better choice.
Or a pre loaded KH reference pH probe tip with semi peramable memberane that can be used for standard 1/2 pH probes would be even better.

I've torn many membranes, maybe I'll try some more.

I suggested this to american marine anbd few others, they just want me to try out some other products, so no one has tried or listened.
I do not want to supply DIY tip for the masses, let me tell you.


But as Yo Han suggest, perhaps the decay of the plants illicts some signal cascadewith algae spores and recruitment perhaps as well.
I might buy that...........

Still, should not activated carbon and large water changes fix that as well for a control test??