mbrigha1

I've heard of people getting air pumps and airstones and I was wondering what the difference is. The way I'm understanding it is that you need an air pump regardless, and an airstone sits either at the bottom of the tank or under the substrate and emits bubbles. Is this right?

-Also, if I want to set up some sort of aeration for my 20 gallon tank, what would be the best setup and what equipment would I need to buy. Thanks.

sirdarksol

An air pump is a mechanism that drives air into the tank.
The air stone (or diffuser) is something attached to the end of the line that comes from the air pump. The air stone turns the big air bubbles into lots and lots of smaller air bubbles, creating more surface area, which is where the transfer of gas happens. The more surface area, the more CO2 gets pulled out of your tank (unless the bubbles are made of CO2, which requires a special setup) and the more O2 goes into your tank.