plenum

[donsauto]

What is a plenum and how do i build one? Also, what are teh advantages??????

[surferdude141]

most people dont use plenums. there arent many advantages but many people nowadays use DSB's (deep sand beds) or a small layer of sand. some even use bare bottom.

[Condiman]

I honestly have tried plenums, DSB, TSB (Thin Sand Bed), and bare. Out of the three I have had the best luck with DSB.

[mjc]

A plenum is an open space of water located under a deep layer of sand at the bottom of the tank. This open space remains primarily anoxic which allows high levels of bacteria that are hypoxic (lives in a low oxygen environment) to thrive.

This low oxygen area conflicts with the high oxygen area of the main water column above the sand bed which results in an extremely slow movement of water through the sand bed itself. This slow water movement keeps the lower areas of the sand bed anoxic, therefore the beneficial hypoxic bacteria thrive.

Studies have shown that a depth of 4 inches to be ideal when utilizing a plenum. A shallower sand bed would be far less efficient. Any depth exceeding 4 inches would impact the system negatively, changing the sand beds redox which would result in nitrogen storage (= not good).

Is a plenum required? Not really, but folks still use them, it's one of many options for setting up your system. Drawbacks is the time and effort required to construct one, the other is the bed tankes up 6 inches or so of tank space (approximately 1 to 2" of dead space comprised of pvc pipes, egg crate material and meshing plus 4" of sand.

[Condiman]

mjc, what an excellent discription :)

[jman785]

Although, a plenum, is a great idea, many people end up making them wrong, and it ends up just being a nitrate factory. So in the end, its not worth even trying :)

Yea, If I Tried Makin It I Would Probably Make It Worng