Horticultural Goals with EI vs what limits "algae"

[Tom Barr]

Our goal is more horticulture, to grow and garden aquatic plants.
So we focus on providing good conditions for plant growth.

Plants, not nutrients define the system and their ability to grow and flourish.
Ever seen a tank with algae and flourishing plants? I haven't. No one likes that look. They want nice healthy plants and no algae.

In tanks where the plants are flourishing and doing very well we see little if any algae. We often assume many things about plants and think they are doing fine and we suddenly see "algae". What is the balance that kept things going well, prior? => the health and growth rate of the plants.

These two may change some and you not notice it, only seeing the algae issue.
Algae are good indicators that something is wrong with the health and growth rates of the plants. Plants themselves can also be indicators and often are. Getting them to grow well again is the key here. EI just rules out non limiting nutrients, it does not rule out too much light or provides ample CO2.

No nutrient dosing method does that. So blame needs to be applied fairly/reasonably and look at the user and their light and CO2 systems much more carefully than nutrients which are rather easy to test and rule out causes.

These tanks can seemingly have little or a great deal of nutrients, both are seen and there is a wide range of observed ppm's for N, P etc. Why is that? Well, light and CO2 play a role also. Less light, less nutrients, also sediment sources can make up for seemingly low water column ppm's and poor testing can also lead to poor conclusions, as is often the case.

So sediment sources + water column dosing are synergistic, they make both methods easier.

As long as the sediment is not messy and you are not making a mess as well, then this is a good method to add to any water column dosing routine.

Less light = less CO2 demand = less nutrient demand. This is obvious to most people. and well supported in research from the Ecology to the Molecular levels.
Fish load also can and does add some variation as well and load of nutrients(plenty for algae to never be limited).

Plant biomass differences between tanks also play roles, and often tanks are nutrient limited which causes issues for CO2 demand(reduces the CO2 demand often several times), so if you add non limiting amounts of nutrients, then you have much more CO2 demand as result, if the CO2 is not adjusted for this, then you end up with algae, not from too many nutrients, rather, lack of enough CO2.

Such indirect relationships cause many to assume algae is limited by nutrients, without considering what and how the plants are affected and without regard or measure of the CO2 and light critically.

This was common decades or so ago, not so much today, but many "still cling to the past". Ironically referring to themselves as new, more evolved methods that dose less than EI etc. If you have low light, then it's not an issue, the tank is not limited by nutrients or CO2. If you have a PO4 limited tank, then you are not limiting algae, you are limiting CO2 demand from the plants.

Very poor conclusions and even worst test method/s.
You can find tanks with no PO4 measured and low limited PO4 and algae ridden. Likewise, where's my algae bloom if limited PO4 works as claimed? If this is true then I should be able to induce algae and run and high risk or a bloom if this theory is correct. However, I've never been able to do it, even at 10-50-100x the suggested amounts to keep the tank limited with PO4. This stuff is easy to test and rule out their potential cause.

So both case experiments where we add lots and add none at all do not explain the results and observations. Yet they still believe it
I guess the world is flat to some folks

You can show reason, logic, experiments, results, examples based on a wide range of observations,(not just the critics' aquarium), suggest test and adding more CO2, reducing light etc to show and demonstrate this.

They can go on with their rants about belief and simply not get that the system in not as simple as they want to try and suggest, yet in some ways, it is very simple: take good care of the plants, then there's no algae issues.

On this point, most everyone is in agreement.



Regards,
Tom Barr

 

[Dmaaaaax]

1.) Can you better define low light vs high light? Before I came to this forum, I considered low light to be 2wpg or less and high light to be 3wpg or more. I thought low light did not require CO2 injection and high light did. But after coming here I see many pushing for ~2wpg or less even with CO2 injection. I know you try to get away from the "WPG" terminology due to differences in tank depths, lumen power, differences in bulbs, distance of light from the tank surface...etc and you use a lux meter, but is there a general cutoff as to when injecting CO2 becomes necessary?

2.) Have you found any effects with temperature and algae or CO2. It has been shown that O2 saturation is less in warmer water. So does temperature effect other things? The reason I ask is that although most tropical tanks hover around 75F, some (like Discus) are kept at 84-86F.

3.) I have never seen this addressed anywhere else so maybe you or someone else has more info or guidance on the following:

In certain cases where your whole tank needs to be medicated...which in turn may make some of your plants unhealthy (thin stems, clear leaves) and possibly your beneficial bacteria as well, algae of all kinds now has an oppourtunity to grow. Do you still continue to use the same dosing method to recover, or should you back down on lights and nutrients for a few weeks? Is it better to do a massive trimming and hope for plant recovery, or should you just toss out everything growing algae and get new plants? I would imagine the bioload goes up because now plants are not helping...their decay is adding to it.

 

[VaughnH]

It is hard to define "low light" without referring to PAR light intensity. Watts per gallon will not work, especially now that so many people use T5HO light fixtures, and so many suspend their lights above the tank. From what I see it appears that "low light" is less than 50 micromols per sq m per sec, but how much less I don't know. I'm using about 50 and, while I don't have hight light, I do need good CO2 to avoid BBA. So, that suggests that low light is something less than 40 micromols. Personally, I don't think the term "high light" is useful now. Either we have a "low light" tank and can do well without CO2 or we don't. Above that level we just have differing growth rates depending on how much light we have.

 

[Tom Barr]

1.) Can you better define low light vs high light? Before I came to this forum, I considered low light to be 2wpg or less and high light to be 3wpg or more. I thought low light did not require CO2 injection and high light did. But after coming here I see many pushing for ~2wpg or less even with CO2 injection. I know you try to get away from the "WPG" terminology due to differences in tank depths, lumen power, differences in bulbs, distance of light from the tank surface...etc and you use a lux meter, but is there a general cutoff as to when injecting CO2 becomes necessary?

2.) Have you found any effects with temperature and algae or CO2. It has been shown that O2 saturation is less in warmer water. So does temperature effect other things? The reason I ask is that although most tropical tanks hover around 75F, some (like Discus) are kept at 84-86F.

3.) I have never seen this addressed anywhere else so maybe you or someone else has more info or guidance on the following:

In certain cases where your whole tank needs to be medicated...which in turn may make some of your plants unhealthy (thin stems, clear leaves) and possibly your beneficial bacteria as well, algae of all kinds now has an oppourtunity to grow. Do you still continue to use the same dosing method to recover, or should you back down on lights and nutrients for a few weeks? Is it better to do a massive trimming and hope for plant recovery, or should you just toss out everything growing algae and get new plants? I would imagine the bioload goes up because now plants are not helping...their decay is adding to it.

1#, I would suggest low light as 30-70 micro mol, 60-120 for med light,and anything over 150 higher light when measured at the sediment. At the surface, anything over 300 is high light, 150-280 medium light,m less than 150, low light.

2#, most folks do not keep planted tanks or fish at 75, more around 78-80F.
84F is fine, but yes, warmer waters hold less gas, but that's less of an issue really, the MET rates are much faster from say 20C to 30C, 2x as much for most organisms. So the rates of growth increase dramatically, cycling time and thus more O2 demand also(fish, bacteria etc).

So you need more CO2, more O2 and nutrients at warmer temps.
If you want to slow things down, go cooler and less light.

When you treat for medical reasons, it's best to have a quarantine tank, but few medications will harm plants IME. Copper obviously, but few use that.

You are dosing to non limiting CO2/nutrients when it's healthy, I see no reason why non limiting nutrients will induce algae before/during or after medicating a tank, you hurt the plants, that,. not the nutrients, is the issue, so dosing less while likely fine because the plants are hurting, not using as much is okay also, but adding less does not save you from algae blooms, good healthy plant growth does.

Plants define the system, not nutrients, unless they become limiting or CO2 etc.
The Paradigm is really add less light when you see algae or do damage to the plants.

Not less nutrients(however, this okay since the light is less correspondingly as well, but leaving the nutrient dosing the same should have no effect).

Just because you can add less, does not imply the results will be any different
Many assume this, and it's wrong and the logic does not follow.
Why would algae be limited in either case: PO4 at 2ppm and at 8 ppm?
NO3 at 10ppm and at 30ppm?

Neither are limiting for the algae.
CO2 is not limiting either.

What's left?
Light....... Plant health/status/sediment disturbance/filter, water changes, organic material, dead leaves etc

Regards,
Tom Barr