I have my 125 native tank up and running. It currently has a Fluval FX4 canister filter. I was going to add an air stone just to help with the live plants. I know some people say they help others say they make no difference. I got to thinking, if I was going to pump some air into the tank I might as well do it via a sponge filter. Any reason not to do this? I figured the more BB the better and the additional filtration would never hurt. I know nothing about them, so I am curious as to your input on them. If I go that way what size air pump is recommended to run one in a 125?