Whats a plenum?

[TigerBarbs]

Was lookin online at live sand and the word plenum came up. It was an egg crate thing under live sand. What does it do?

 

[Rutrag]

A plenum is basically a water space below the substrate with very little water circulation. The idea is that the water in there has little to no oxygen which is the environment in which denitrifying (?) bacteria thrive. These are the ones that trun nitrate (the end product of the nitrogen cycle in an oxygen rich envrinment) into nitrogen and other products. I've read mixed reviews from folks who have used them, and most people beleive you accomplish the same thing or better with just a deep sand bed. I've never tried one, so I can't speak from experience at their function.

 

[TigerBarbs]

O okay thanks

 

[Wy Renegade]

Rutrag hit the nail right on the head; a plenum is a plastic barrier of some type which creates a anaerobic zone at the bottom of the aquarium. Generally because of the lack of oxygen, this zone also is more acidic than normal. The value of using one, is as stated, greatly debated with many saying they get the same results from a properly set-up DSB.

Here are a couple pictures for you:

 

[TigerBarbs]

Thanks guys! Just curious as to what they were and the whole idea of one. Got it now ,.

 

[toddnbecka]

I've seen a couple different brands of filter media turning up lately that claim to support anaerobic bacteria for denitrification. No clue whether they're useful, but I think I'll just stick with water changes.

 

[BrittneyFranco]

nice things...it's like a focus..when you have understood how it works everithing become very simple