Nutrafin CO2 harmful to killifish?

[gary35111]

I have Nutrafin CO2 for the plants in my tank. The Nutrafin CO2 cannot be "turn off". I have light on for 8 - 10 hours per day and before 10 pm, I will turn the light off. I

I have heard of CO2 poisoning of fishes and concern if the continuous release of CO2 in my tank will post a health threat to the other aquatic lives in my tank.

I have a trio of kid killies, a pair of Ottos and 20 cherry shrimps (yeah! now they are healthy, swimming and eating spirulina algae tablets. Bought them from LFS in a pack of 20. Guess the previous shrimps I had were sick or something.)

[CM Media]

My CO2 is running 24hours a day for a 3ft tank where I've various killifish and shrimps inside. So long as you lower the rate CO2 is injected into the tank everything should be fine.

[TyroneGenade]

I have heard of CO2 poisoning of fishes and concern if the continuous release of CO2 in my tank will post a health threat to the other aquatic lives in my tank.

It is unlikely that you could get enough CO2 into the tank to poison your fish. The problem is O2 concentrations.

I assume you have a heavily planted tank? Plants need O2 too. At night they will respire and use O2 but will keep all the CO2 back to use during the day. This is not the case in the day where the plants will use CO2 and produce O2 boosting O2 levels. At night the plants will also take up CO2 but put no O2 back. This can lead to problems.

As there are now more than double the number of organisms using O2 the water O2 concentration will fall. If it falls too low the fish can suffocate from O2 deprivation not CO2 asphyxiation.

Watch your fish in the morning? Are they hovering around the water surface? Then quite likely you may be in for trouble as this means there is little O2 in the water and they are having to try and get more and the most O2 will be had at the water surface. If this isn't happening then matters are most likely fine.

My suggestion is that increase aeration at night if this is happening. Increased aeration will help keep the water full of O2 and drive off some CO2 in the process.

Kind regards

[gary35111]

Thanks for the information. Okay, I need to get this straight (maybe I have forgotten something I learn in elementary school). If there is 'light' and CO2, there will be a process of photosynthesis by plants/aquatic plants and O2 will be released, right? This is what I have learned and know.

It is just that when Mr Tyrone (the biochemist) talk about 'day' and 'night' in his reply, it got me thinking. Do plants/aquatic plants only perform photosynthesis during the day? Man, I sound like a kid. Does it matter if it is during the daytime or nightfall? As long as I have my light shinning on my aquatic plants and supply of dissolved CO2, even if it is night time, will there still be photosynthesis? ...really sound so stupid.

What I learned and know is that as long as there are light, CO2 and plants/aquatic plants, there will be photosynthsis. Correct me if I am wrong.

Gary

[TyroneGenade]

Gary... I will have to explain elsewhere as this can get a bit complicated without illustrations.

I will probably dump the info under the planted tank section tomorrow or so... You are kind of right however but not entirely.

Keep well

[stormhawk]

Gary, you're correct. Photosynthesis occurs in the presence of light, CO2 and the plants themselves.

When it is nightfall the plants do the reverse and take in O2 and give out CO2.

What Tyrone is trying to say is that CO2 levels rise at night when the plants take in O2 and release CO2. This, coupled with a 24hour release of CO2 via injection from a CO2 cylinder or tank, can quickly "suffocate" the animals in the tank. It is therefore necessary to provide some sort of aeration during dark hours to ensure that the CO2 levels do not become lethal to the livestock in the tank.

Really simple isn't it?

[TyroneGenade]

You would have to put a lot of CO2 into the tank to gas the fish... the problem is pH. CO2 combines with H20 to form an acid. If your water isn't bufferred properly then the pH can drop like a stone. This is very bad news as this can cause the pH of the fish's blood to drop too. If it drops much below 6.5 the hemoglobin cann't hold onto O2 and the fish effectively suffocate.

Plants will produce acid at night but will NOT release CO2.

I've posted the photosynthesis post on in the planted tank section.

Regards

[stormhawk]

Hmm.. if plants produce acid at night but do not release CO2, then what I learnt during science class at school was all crap.

Someone or somebody needs to revise them school books.

[TyroneGenade]

You are right, some one needs to revise the school books. Most are filled with crap.

Where it not for my Botony Prof---who kept planted fishtanks---I would not know that aquartic plants hang on to the CO2. The info just isn't widely known.

For many plants (trees, shrubs etc...) what you learn in school is 100% correct. But most grasses use CAM photosynthesis and so also don't release CO2 like dessert and artic and aquatic plants.

Just another case of our teachers feeding us half-truths...