the 29 with two comets an a silver minow an one mystery snail an a small pleco

the pvc construction is a moving bed I made with beads my daughter had for last year xmas. they are the star shaped ones an the square shaped double holed it has been up an running for five days its the only filter running in this tank. I have had no problems with it plus it looks cool when you look at the bottom tee an all the beads are moving around. air pump thirty gallons, sponge for mechanical filtration an a scrupper inside for added bio . 1/4 cup of carbon behind the sponge next project will be a canister filter . just got to figure what fish to add besides my test subjects lol oh yeah an some maple leaves at the bottom under the gravel it dropped my ph. from 7.5 to 7.0 in one night holding at 6.5 the one piece of java moss spread in one night to four pieces.. will keep posted