good/safe CO2 levels?

[current516]

I've got my DIY CO2 going pretty well now, and I'm trying to slowly boost my CO2 levels. I can get them pretty consistent with a heater on a timer, and alternating 2 liter mixes.

My question is this, how high do you all let your CO2 levels get before worrying about your fish? I'm trying to figure out what levels to shoot for.

I realize it probably depends on the fish, but I'd be interested in what you are doing as far as CO2 levels. And any problems with CO2 and fish dying. Chuck's planted aquarium says over 25 can be harmful to fish but it seems that people are going higher than that safely?

 

[Wizzard~Of~Ozz]

It's funny, I keep hearing that levels over 25ppm *can be harmful to your fish. but I run mine at about 40ppm and the fish are fine, Co2 and O2 coexist in the water, one does not displace the other and with my high Co2 level I get O2 saturation at around 6:00-8:00pm..(either that or I've carbonated the water

I would be interested in hearing some qualifications to 25ppm+ is harmful to fish.

 

[malkore]

40ppm is as high as you need to go. anythign above that is just wasted CO2. A lot more than that, and you could harm the fish.

But for the record, I accidentally ran 80-90ppm for a whole week, and my fish were fine. It was the pH/Kh testing that revealed my elevated levels.

 

[current516]

Thanks guys.