Tetras and CO2

Hi Prof

I introduced 10 lemon tetras about a week ago to my 60L planted tank of which only 1 is left. The other tank mates are 1 Panaque Maccus, 1 blue ram and 8 male hybrid endlers and 1 male betta. The tank setup is ADA Amazonia soil and CO2 at 1bps. All the other fish are happy and lively and doesn't seem bothered about the CO2 in the least. The lemon tetras all started going loopy when they swim almost like a swim bladder problem. Could this be the CO2 causing this or just a weak batch?

 

Hi Double-D,

I need to know a few more things before I can answer. What is the carbonate hardness of your water? How long ago did you set up the tank with the ADA Amazonia Soil. Do you switch off the CO2 at night?

Kind regards,

Dirk

 

GH = 8
KH = 3
pH = 6.6 - 6.8
Tank was setup 6 weeks ago with the aquasoil

 

Do you switch off the CO2 at night?.

 

Sorry about that. CO2 is DIY that's why I took a sample an hour after lights on. But they all started acting up during the late afternoon and then my plants are pearling like mad.

 

But do you switch off the CO2 at night? Third time I ask this.

 

CO2 is DIY yeast so I can not shut it down

 

Hi Double-D,

Thank you for clarifying this issue for me, because now I can give you a precise diagnosis. You have killed these fishes with your CO2 because it is unregulated. With 3 degrees carbonate hardness you have no buffering against the effects of the CO2 on the pH. The constant stream of CO2 would completely saturate your water which would explain why your plants pearl so much in the afternoon. During that time your water oxygen levels would also be very high which would explain the fish swimming around like that, they were most probably having embolisms in their gill (bubbles in the blood). Then when you switch off your lights, the CO2 will acidify the water to a pH of below 4 and will kill your fishes, I am surprised that you have any fishes in your tank that have survived. The very least that you must do is remove the CO2 supply at night, you CANNOT run it through the night. All automated CO2 systems switch off at night. You also must have above 4 degrees carbonate hardness in order to use CO2 fertilization or else the pH may be 6,5 during the day but below 4 at night and no fish can survive such pH fluctuations in the long run. Sorry to disappoint you but you need to reconsider this very carefully.

Kind regards,

Dirk

 

Is there something I can use to lift the carbonate hardness of my water?

 

Yes, you can add Calcium Carbonate, but you need to add a little and then measure carbonate hardness until you reach the desired level.

Most importantly, you cannot run the CO2 when the lights are off.

 

@Double-D

In the articles section I did a write up on the cautions of CO2. Whilst it mainly talks about pressurized co2, the principls are the same. You say you can not shut it down.. I say you HAVE to. This is one of the many draw backs to the diy yeast.

Sent from my GT-P1000 using Tapatalk 2

 

What I can suggest is that you put a T-joint into the airline that leads the DIY CO2 from your yeast containing reactor to the aquarium. Then put a length of air pipe on the T and just put a small airtap (you can get these from the irrigation shop) or a clamp on the line, and at night you open the tap or release the clamp. Then the CO2 can just blow off into the atmosphere during the night and not cause the pH drop in the aquarium. If you forget to clamp or close this vent during the day, it is also not a train smash you can reconnect it whenever you want. At least you will not be adding the CO2 at night then.

Kind regards,

Dirk

 

Hello professor

I was wondering... if you have no animals in the tank, can you then leave the CO2 on 24/7 or would it still be more beneficial for the plants to leave it off at night?

 

In my opinion no, because the pH no biological organism, whether it is a plant, or animal/fish or bacterium can cope with those swings in pH. So the plants won't survive this either in the long run.

People misquote me on saying that I am opposed to the use of CO2 because I have often explained that I prefer to not use CO2 in soft water because it causes pH swings, but I am actually not opposed to it at all, but if you use it without regulation and on water which has a low carbonate hardness it is a ticket for disaster and is far worse to use than if you do not use it at all. Bottom line is using CO2 is going to cost you a lot of money and there are alternatives that do not work as well, but you can certainly have a nice planted tank without CO2 as well.

Kind regards,

Dirk

 

Thanx a lot,

agreed.