i considered the reverse flow with a prefilter like that. Does he have many fish in the tank or mainly just inverts? Part of the reason i want to do a plenum is that the tank has a sizeable fish load and im sure they will want to add to near the limits of what can be kept, and there is no sump no refugeum so there is no nitrate removal unless i add a plenum or dsb. I would do a sump, but again the budget is an issue. thanks for the help.