What Is A Plenum Filter????

[snaza]

im setting up my reef tank and i read i need a plenum filter? its goes under the sand bed. first what should i use as my sand bed and how much? do i need a plenum filter? are they expensive?

 

[bertoni]

I wouldn't use a plenum. There's no evidence that they work. The basic idea is to create an area of open water at the bottom of the tank. Well, the area is not open to the surface.

There's a study of them by R Toonen on AdvancedAquarist.com, I think.

There's a sticky note at the top of this forum on substrate choices.