I would use LECA over pea gravel any day. It weighs considerably less than gravel. You can find it under the names Hydroballs (ZooMed) and Hydroton. The ZooMed product may be easier to find as Petsmart carries it. I prefer Hydroton, as it is a better product, quality-wise.

You will also need atleast three filters per tank. Just kidding! Seriously, they only tanks of mine that have filters are the rain chambers/tadpole tanks.