Too much CO2 using DIY system?

During the last several mornings, before the light is starting, I see my fish at the surface breathing heavily.

I have a lot of plants, and I'm adding a bit of CO2 to the aquarium (using a DIY mechanism).

I'm almost sure that the problem is too much CO2 at the morning, as a results of the plants breathing O2 at night, and not because of the CO2 injection.
Still, I thought to ask for opinions before I start cutting down plants.

I'll upload pictures later on today, so you can see what I mean.

I understand that when it's dark, plants actually produce carbon dioxide. Since the DIY carbon dioxide system does not shut off at night, the oxygen dissolved in the aquarium water gets used up, and the fish gasp for air. In addition, those DIY systems produce more than carbon dioxide. If you've ever tried to make wine or fermented dill pickles you know that the fermentation process can produce some interesting odors. On top of that, carbon dioxide systems can drastically change water chemistry, so you really have to be careful with them. If you want a really lush, show class aquarium CO2 supplementation and special lighting are necessities, but you can have a nice, working class planted tank by adding one of the commercial clay products to the aquarium substrate. I like pure laterite, because you can just dump it on top of the existing gravel. Laterite is supposed to require some iron supplementation, but it's best to go easy on any aquarium chemicals. If you choose plants that are easy to raise in your particular aquarium water, you'll have a nice aquascape without all of the CO2 negatives. The bottom line is you should think about keeping all of the plants and ditching the CO2 maker.

johnarthur wrote:

I understand that when it's dark, plants actually produce carbon dioxide. Since the DIY carbon dioxide system does not shut off at night, the oxygen dissolved in the aquarium water gets used up, and the fish gasp for air.

I was thinking about it, but we have air conditioning running all night long (don't ask me why - that's my wife...), so other then my soar throat, I think the DIY system is slowing down drastically.

In addition, those DIY systems produce more than carbon dioxide. If you've ever tried to make wine or fermented dill pickles you know that the fermentation process can produce some interesting odors.

WOW - never knew that!
Do you know what is it? I guess it dissolves in my water, and god knows the effects...

On top of that, carbon dioxide systems can drastically change water chemistry, so you really have to be careful with them. If you want a really lush, show class aquarium CO2 supplementation and special lighting are necessities, but you can have a nice, working class planted tank by adding one of the commercial clay products to the aquarium substrate. I like pure laterite, because you can just dump it on top of the existing gravel. Laterite is supposed to require some iron supplementation, but it's best to go easy on any aquarium chemicals. If you choose plants that are easy to raise in your particular aquarium water, you'll have a nice aquascape without all of the CO2 negatives. The bottom line is you should think about keeping all of the plants and ditching the CO2 maker.

I'm gonna upload some photos later on, tell me if you think the tank can make it without the CO2.
Truth - the CO2 had a great impact on the plants, and I thought I'm not over dosing, because it's a DIY.

Commercial CO2 systems are pretty expensive, but they're also quite a bit better and more controllable than the DIY kind. When yeast and sugar water get together they make alcohol and eventually vinegar unless the whole thing gets too warm and just rots. Carbon dioxide is only one of the fermentation byproducts. I'm not sure what the others are; mold is one of them. If you get a chance, you may want to read Guide to Aquarium Plants by Barry James. It's short, well organized, and very informative about the requirements of specific plants.

And please do post the pictures when you get a chance. I love looking at aquariums.

PS: Talk about air conditioners working at night, here in Phoenix the low temperature was in the 90s.

Oh, so that's why my CO2 bottle smells like vinegar whenever I go to dump it. Sometimes the obvious is just so obvious. Another of life's great mysteries has been solved. Thanks John.

It would not surprise me too much if a few alcohol fumes and mold spores also managed to migrate into an aquarium through a DIY CO2 system. That said, I would still like to try one in a small aquarium with no fish. Maybe then I could get wealthy in the plant selling business, since all these angelfish aren't likely to bring untold wealth.