smaller clams are harder to keep because they have different feeding needs...at that small a size they arent very dependent on photosynthesis.
heres my sump
[img]http://ca.msnusers.com/_Secure/0LQCHFUgQHnJRx7dZKPgxSXvYS!80Mfaa3BVSUQaCUbx*wAENr ubfQuK3MByG9eQDITP!WdEfn3U/sump.jpg[/img]
and the refugium
