Co2 Question

[capper]

I was at a petshop recently and was cinsidering buying a Co2 machine so that I could get some nice plants that require Co2. One of the staff at the shop told me that you cannot use a Co2 machine unless you have an undergravel filter. Is this true? If so, what is the reason?

 

[Lotus]

No, it's not true. What is true is that the more turbulance/surface disturbance you have in a tank, the more CO2 you will lose through gas exchange at the surface. Even with high surface disturbance, you will still get some CO2 into the tank. It's important to note that if you don't have enough surface disturbance, your fish may suffer from low oxygen in the water at night when plants aren't producing oxygen.