NO3:PO4

[albert_dao]

Yah, if I were to venture a guess, I'd first tackle the flow. Looks like you have a pair of Apex pumps in there, which would normally be sufficient, but your rockwork is really dense. A couple smaller pumps (Sicce Xtreams, etc) behind the rock would do wonders. That or you could just open up the rockwork.

Also, how is your sump set up? Are there any large piles of detritus?

Nice Candy Basslet btw!