Green dust algae and herbivores

freemann · Apr 4, 2006

Re: Green dust algae and herbivores

VaughnH

You may have already answered this, but do you check to see how much your CO2 drops the PH? Take a tank water sample, let it outgas for a few hours, measure the PH and compare to the in-tank PH. It should be .8 to 1.1 lower in the tank to have enough CO2. This technique removes the effect of other acids in the water or something amiss with the KH reading.

Ph is 0,74 on average lower than the Ph on the degased water, at the lower swithing on point of the ph controller it is 0,83 checked tonight but I have observed it before aswell when I was out of CO2 for a day or two before I filled the CO2 tank again.

Tom I will push the CO2 further down than this and switch it off at night now it stays on. I was always wondering won't this fluctuation stress the fish every morning? Pushing the Ph down by one degree I have seen to be quite stressing for the fish. You yourself say "Just adjust it down slowly" what of this 1 degree every morning?

Ok all fixed ph probe recalibrated, CO2 keeps aquarium water 1.1 degrees lower than degased aquarium water.
Thanks guys.
Freemann

Tom Barr · Apr 4, 2006

Re: Green dust algae and herbivores

The reason for slow adjustment is for fish health based on gassing them. Folks get carried away and over do it, then get gun shy from then on.

It's not pH adjustment that stresses fish, it's high levels of CO2 and/or low levels of O2 in conjunction)
Etch that into your brain.

We add CO2 not for pH control, but rather, for the plants.

pH is simp,ky part of the method we use to measure the CO2. that's all. Natural planted lakes have pH changes of 2-4 ph units. pH's starting in the AM from 6-7 going up to 9-10 in the late afternoon.
Happens daily.

There are plenty of fish.
The best bass fishing lakes in the world actually go through this cycle daily.

Sounds like you are light on CO2, about .2-.3 pH units or so.
Adjust to .1 and then wait 1 day, then note fish, make sure you have decent surface movement, losing a little CO2 is okay here, you can add more to account for this lost easily and it'll help control the CO2 better(prevents high spikes of CO2 build up, makes balancing the CO2 ppm easier).

Make sure you do this, the water can can have a slight ripple.
Not alot, but surface movement is a must.

Off at night will degas the high level of CO2, something not good for fish especially when you have the lowest O2 levels as well, note, you do not have a O2 controller/O2 gas tank in here, I'd say that is more important to fish health than pH variation certainly.

So rather than having a high chronic level of CO2, you now have only a spike of CO2 during the day when the plants also produce high O2 levels.

Amano also does this.
I've done it for I guess 15 years.

We add CO2 only, and I mean only to fertilize the plants. Why add something like this when we do not need it?

Adding some surface movement will lose a little CO2 during the day and turning the CO2 off at night will save a lot and add more O2 at night allowing the bacteria to break waste down better and the fish to breath easier.

Basically the method of turning it off at night will allow you much more wiggle room at higher levels without harming the fish than any other method.

And given that is the greatest concern to our fish, seems to be the wisest approach.

Regards,
Tom Barr

freemann · Apr 5, 2006

Re: Green dust algae and herbivores

The reason for slow adjustment is for fish health based on gassing them. Folks get carried away and over do it, then get gun shy from then on.

It's not pH adjustment that stresses fish, it's high levels of CO2 and/or low levels of O2 in conjunction)
Etch that into your brain.

We add CO2 not for pH control, but rather, for the plants.

pH is simp,ky part of the method we use to measure the CO2. that's all. Natural planted lakes have pH changes of 2-4 ph units. pH's starting in the AM from 6-7 going up to 9-10 in the late afternoon.
Happens daily.

There are plenty of fish.
The best bass fishing lakes in the world actually go through this cycle daily.

Sounds like you are light on CO2, about .2-.3 pH units or so.
Adjust to .1 and then wait 1 day, then note fish, make sure you have decent surface movement, losing a little CO2 is okay here, you can add more to account for this lost easily and it'll help control the CO2 better(prevents high spikes of CO2 build up, makes balancing the CO2 ppm easier).

Ok I relialize that we add CO2 for the plants not Ph control.
Let me tell you my impressions though, Ph controller was adjusted down to 1.1 degrees from the degaused tank water, fish adjusted fine last night but after the switch off of the CO2 during the night, Ph was around 6,96 in the morning 11 am and this was when I switched on the controller and the distribution of CO2 (lights come on at 2 pm) by that time Ph was at the proper range but the fish were all in the surface aswell, took them more than 6-7 hours for all to leave for good the surface (charachids, gouramis do much better pencilfish seem to suffer most). So what are your suggestions of the on - off of the CO2 in relation to the lights? If I turn on CO2 when lights come on it will take 4 hours for the CO2 to come down which seems to me that makes it the same like having higher Ph (less CO2) continously (fish weren't stressed at least that much with less CO2 all the time.

Adding some surface movement will lose a little CO2 during the day and turning the CO2 off at night will save a lot and add more O2 at night allowing the bacteria to break waste down better and the fish to breath easier.

Ok surface movement is sufficient.
I am adding a bit more KNO3, PO4 one day before WC.
Tank looks fine, yellowing is always there.
Freemann

mfbonfante · Apr 5, 2006

Re: Green dust algae and herbivores

I have a couple of questions at this point:

- Is it advisable to leave a diffuser running with an ordinary aerator to maintain O2 levels high? Is there any problem with this?
- When you mention “turn CO2 off when lights are disconnected”, are you actually switching the CO2 controller off?

Thanks,

Mariano

freemann · Apr 5, 2006

Re: Green dust algae and herbivores

Is it advisable to leave a diffuser running with an ordinary aerator to maintain O2 levels high? Is there any problem with this?

When while the CO2 is diffusing or during the night?
Won't the aeration push the CO2 even higher and thus make it even more difficult to push the Ph back down though CO2 diffusion?

When you mention “turn CO2 off when lights are disconnected”, are you actually switching the CO2 controller off?

Yes switching the controler off switches the CO2 valve off aswell.

mfbonfante · Apr 5, 2006

Re: Green dust algae and herbivores

When while the CO2 is diffusing or during the night?

During whole day. That will cause O2 to high level, ever.

Won't the aeration push the CO2 even higher and thus make it even more difficult to push the Ph back down though CO2 diffusion?

I think aeration will agitate water helping CO2 to be released from water column. This will lead an increased CO2 consumption for the same targeted PH, but it would be a minor issue, IMO. But, perhaps there is something else I am not considering.

VaughnH · Apr 6, 2006

Re: Green dust algae and herbivores

Airstones or bubblers do not add significant O2 to the water. They work by disturbing the water surface and creating water currrents so more O2 can dissolve thru that surface. But disturbing the water surface also increases the rate at which we lose CO2 from the water to the air. So, my opinion is that running an air bubbler while the CO2 is turned on is not a good idea. Anyway, our goal is to saturate the water with O2 from healthy, fast growth of the plants.

Tom Barr · Apr 6, 2006

Re: Green dust algae and herbivores

freemann said:
Let me tell you my impressions though, Ph controller was adjusted down to 1.1 degrees from the degaused tank water, fish adjusted fine last night but after the switch off of the CO2 during the night, Ph was around 6,96 in the morning 11 am and this was when I switched on the controller and the distribution of CO2 (lights come on at 2 pm) by that time Ph was at the proper range but the fish were all in the surface aswell, took them more than 6-7 hours for all to leave for good the surface (charachids, gouramis do much better pencilfish seem to suffer most). So what are your suggestions of the on - off of the CO2 in relation to the lights? If I turn on CO2 when lights come on it will take 4 hours for the CO2 to come down which seems to me that makes it the same like having higher Ph (less CO2) continously (fish weren't stressed at least that much with less CO2 all the time.

Ok surface movement is sufficient.
I am adding a bit more KNO3, PO4 one day before WC.
Tank looks fine, yellowing is always there.
Freemann

Okay something is not right and it's CO2 related here.
You should not have that problem.

4 hours to drop the pH?
So how can the tank ever respond to increases and changes in the CO2 if it takes so long??????????

I knew this was CO2 all along and now I know it is.

Here's the problem: response times.
Even with the pH controller, it would take several hours to get the CO2 up and the control you actually is very poor.

That's why you have the stunting in some plants and the types of algae ypu have.

How to solve the issue?

More flow through the CO2 reactor, the higher and better mixed the water is going through that and also the more flow and evenness of the CO2 rich water coming into the tank, the better.

Even with your pH controller, the rate of response is still poor, which is why you still got algae even though the pH seemed okay.

If you use a pH controller/controlled system, it's always better to have a much greater over sized mixing pump and reactor relative tio the tank's volume and dimensions.

Often the pH will appear to be okay at different places in a larger tank, but the reality is something else.
The other thing, the pH probe might be placed close to the outflow of the reactor, thus not telling you if the pH is low elsewhere, sumps can have similar issues.

4 hours is simply too long, it should be 30-60 minutes or so.

Adding CO2 accurately to smaller tanks is much easier for this reason.
And that makes sense as well.

Regards,
Tom Barr

freemann · Apr 7, 2006

Re: Green dust algae and herbivores

Okay something is not right and it's CO2 related here.
You should not have that problem.
4 hours to drop the pH?
So how can the tank ever respond to increases and changes in the CO2 if it takes so long??????????

Well it seems long to me as well, but bubble counter bubbles fast, and I can hear the CO2 been injected (CO2 input is just before my 2 micron filters and after the 2.500 lt quietlife pump), could it be the fact that Kh is 8 that makes the CO2 go down so slow? I am going to recheck for leakages.

Here's the problem: response times.
More flow through the CO2 reactor, the higher and better mixed the water is going through that and also the more flow and evenness of the CO2 rich water coming into the tank, the better.
Even with your pH controller, the rate of response is still poor, which is why you still got algae even though the pH seemed okay.
If you use a pH controller/controlled system, it's always better to have a much greater over sized mixing pump and reactor relative to the tank's volume and dimensions.

Concerning response times once the ph is pushed down at the required value response is ok cause the ph won't be allowed to move above the switch on value of the controller which is just 0.05 from the desired value anyway, there the response seems pretty fast and the ph goes down from this valve on value and not further up and then down.
Ok as alternatives I have to options here I can use a huge DIY reactor I have lying around unused) or use 2 wooden stones under the input of my big circulating pump it is strong and I could setup the whole thing pretty fast if nothing else for experimental purposes, will I be able to push the CO2 down by 1.1 degree by using the wooden stones or I could do with less cause of the bubbles?

Often the pH will appear to be okay at different places in a larger tank, but the reality is something else.
The other thing, the pH probe might be placed close to the outflow of the reactor, thus not telling you if the pH is low elsewhere, sumps can have similar issues.

Well probe has a fast response on big ph changes (which means it is ok), very precise on calibration on both values (7-4 testing liquids] so np there, it is also placed next to the water input and the output is 1.5 meters away, the flow of the recalculating pump is passing from it so no possibility of stagnant area. So this possibility seems improbable.
Thanks again Tom

Tom Barr · Apr 7, 2006

Re: Green dust algae and herbivores

No, the response time of the pH probe is not the issue, you should not have any issues dropping the pH down after the night to the right range inside 1 hour's time.

Otherwise, the CO2 reactor/mist etc is woefully underpowered and is the Achillies Heel.

Doesn't matter how accurate the pH probe is, the controller etc, it'll still work, but it'll take several hours, but then there is already a deficiency......

The pH probe does not tell you what the CO2 level is at the leaf(this is where it's important), only where it is placed in the tank.
Just be aware of the system and the assumptions here.......it does not imply that the entire tank is well mixed and has access to the same CO2 that the tip of the probe does, there is variability.

I would add more current to the tank, I would also use a nice large CO2 reactor with a higher powered pump or a combo of both and mist.

The pH wills till drop the same etc, the CO2 ppm is the same no matter if the KH is 3 or 8 etc.

pH controllers really do not have much better than 0.2pH units worth of play in their on/off cycling.

But 4 hours to knock a pH down to good levels means the system is underpowered and has a poor response time, I know you cannot see it, but I've done this too many times not see this and have seen folks have this same issue in the bay area on no less than 3 tanks about the same size.

I have to run to the lab, but I'll get back with you today or sometime this weekend with some pics and ideas that will help improve things for the tank, they don't cost much etc either and will improve things no matter what.

Regards,
Tom Barr

freemann · Apr 8, 2006

Re: Green dust algae and herbivores

Just some observations increased CO2 passthrough with the needle valve I turn off C02 an hour after lights turn off now Ph at 2 pm next day when lights come on is 6.69 the ph takes 1 1/2 to come down to 6.17 and switch off still the fish come on the surface the operculums on the them are open on the underside. Current is visible and enough. Could it be that this amount of CO2 is simply to much in the first hours when the lights come on and O2 hasn't been produced in sufficient amounts from the plants?

Tom Barr · Apr 8, 2006

Re: Green dust algae and herbivores

If the current is enough, then there should be plenty of O2.
If you have good even current in the tank and good surface movement, there should not be a problem.

If fish are coming to the surface, back off the CO2 a tad.
1.5 hours is better than 4 hours.
Give this a whirl and see if there are improvements over the next few days.

Regards,
Tom Barr

PeterGwee · Apr 8, 2006

Re: Green dust algae and herbivores

Tom, since the mist is not as efficient in dissolving CO2 as compared to a reactor, does the response time become longer? (I still cannot determine my response time as my pH keeps dipping throughout the day....

). Maybe a more detail look into the issue would be good with pictures/diagrams.

Regards
Peter Gwee

VaughnH · Apr 8, 2006

Re: Green dust algae and herbivores

I'm not convinced yet that the mist system is less fast in dissolving CO2 into the water - less efficient, yes, but probably just as fast if not faster.

PeterGwee · Apr 8, 2006

Re: Green dust algae and herbivores

VaughnH said:
I'm not convinced yet that the mist system is less fast in dissolving CO2 into the water - less efficient, yes, but probably just as fast if not faster.

VaughnH, do you get a fast response time with the mist method then? 30ppm within an hour and stable throughout the day?

Regards
Peter Gwee

Tom Barr · Apr 8, 2006

Re: Green dust algae and herbivores

PeterGwee said:
Tom, since the mist is not as efficient in dissolving CO2 as compared to a reactor, does the response time become longer? (I still cannot determine my response time as my pH keeps dipping throughout the day.... ). Maybe a more detail look into the issue would be good with pictures/diagrams.

Regards
Peter Gwee

Well , the response time should in theory, be slower, it depends on the flow mixing rate and direction(downwards vs upward where the gas bubbles might be lost to the air above).

The other thing, the mist does not entirely dissolve, so the issue is not something you can directly measure like the pH/KH for CO2.

The gas bubbles hit the plant and increase growth, it does not dissolve entirely into the water so you can measure the response time.

The only way to really address the issue is to measure the O2 evolution from plants, label the CO2 supplied and compare to a similar set up without the mist etc.

Regardless, you should see a difference in pearling in the first few hours of the mist vs the normal dissolved method.
"Bubbles stuck to plants" etc can be done by aeration if yoju want to see if the pearling is due to other gases etc or if it's due to plant growth, it's not something we might confuse, we look at plants a lot and know if they are growing actively and pearling for the most part. You can certainly tell after a few days.

Regards,
Tom Barr

Regards,
Tom Barr

PeterGwee · Apr 10, 2006

Re: Green dust algae and herbivores

Tom, so what's a reasonable response time for mist method? Not sure if I should be concern of the response time since I can see loads of mist all over the tank once the CO2 starts along with the lights?

Regards
Peter Gwee

VaughnH · Apr 10, 2006

Re: Green dust algae and herbivores

PeterGwee said:
VaughnH, do you get a fast response time with the mist method then? 30ppm within an hour and stable throughout the day?

Regards
Peter Gwee

If the response time is the time for the plants to pearl, I get a much faster response with mist. I so rarely measure KH and PH, almost never, unless I think I have a problem, that I don't know how fast the PH responds. After my last fiasco I did measure PH an hour after lights on and it had already dropped to where I wanted it. An hour later it hadn't changed.

My last fiasco was with my spray bar. I learned the hard way that algae (?), probably diatoms, grow inside the spray bar, gradually blocking the holes and damming up the inside. That led to the CO2 bubbles being stopped midway down the tube, accumulating into really big bubbles, then burping out. The net result was that my CO2 ppm dropped considerably, and I began growing BBA again. I hadn't been paying enough attention and didn't catch this as soon as I should have.

Now, I am not using the spray bar, just letting the powerhead pump out across the back of the tank. Each CO2 bubble gets blasted out as a ton of microbubbles, sorta chug, chug, chug style. I now have the bubble rate readjusted to get the ppm back to about 30-40 ppm again. I had to make a bubble counter out of a syringe to be able to adjust it right. And, yesterday shortly after lights on, one bulb made a loud pop and quit! It's an AH Supply bulb, only a couple of months old.

Tom Barr · Apr 10, 2006

Re: Green dust algae and herbivores

1 hour you should see pearling on most plant species.
with less/lower light, probably takes a little while longer.

1 hour or less is a decent response time to knock the pH down/get enough CO2 into the water.

It really depends on the tank's volume/mixing rate, flow characteristics etc.

Larger tanks simply take longer unless you have a lot more flow.
And they can have zones that are CO2 poor and CO2 rich depending on the set up.

Regards,
Tom Barr

VaughnH · May 1, 2006

Re: Green dust algae and herbivores

I know this is an old thread, but I have been waiting for some conclusions. First: about the herbivores: what were they, are they common, and are they a problem?
Second: what should we, who are cursed with green dust algae on our tank sides, do to exorcize ourselves? I think you said to just let it finish its growth cycle and it goes away by itself?

Green dust algae and herbivores

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