It is a 20L with enough water in it to cover his rocks and filters. I have 2 internal filters, one behind the slate that makes a little waterfall and one that lays down on the other end with a spraybar that sticks up and makes it rain. It only rains during the day because it drives me nuts at night. LOL
Well yea, I think 20L comes out to about 5.5 g or so. I wanted to do a setup like that with a canister filter and maybe a spray bar. I need silence when i sleep, it would drive me crazy too lol. Black Sun are you gonna keep anything else with your crab?