Co2 Killing Fish?

[gizmo001i]

Hi,
I fitted a DIY CO2 system to my 30" tank a couple of days ago. I used an end of a bottle as a bell for the CO2 to feed into and a 2 ltr bottle for the yeast/sugar mix. I had read that this is a suitable way to allow the CO2 to mix with the water. However, since fitting the sustem to my tank, I have lost 2 fish which seemed otherwise to be in good health. I had noticed that the fish were swimming into the bell. Could it be the CO2 system that killed my fish, I have since removed it from my tank incase it is the culprite. Any ideas would be very welcome.

 

[zig]

I doubt its the DIY CO2, i dont think you will dissolve enough CO2 into the water just using an inverted bell, i would look elsewhere, have you checked for the presence of ammonia? and is this tank cycled or just newly setup?

 

[gizmo001i]

Hiya,
The tank has been running now for about 3 months with no problems. I have checked all my stats and they are well within specs. Nitrite is 0, Ammonia is 0, PH is 7.2 and Nitrate is at 10. The only change has been the CO2 setup.

 

[zig]

Have you measured how much CO2 is dissolving in the water, using Ph and Kh testkits? too much CO2 and you will kill fish, although as i say the bell method is usually totally inefficient and i doubt this is the cause, but cant tell unless you measure how much CO2 is diffusing into the water.