Plenum

[waterbaby76]

Ive heard a lot about a Plenum System but dont understand one thing--what do you need to do to clean it? Doesnt "bad stuff" collect on the bottom?

 

[krazzydart]

from my understanding the bacteria is taken care of by itself..... the waste is eaten by the bacteria in the plenum ..... you need a good 3" sand base..... I have one in a reef of mine and don't notice any diffrance between that one and one with no plenum ....

 

[bobber]

A plenum is where there is NO oxygen at all. There is a different type of bacteria that lives in that type of environment that convert nitrates into harmless nitrogen gas. There is NO NEED to clean it. Like stated before, you MUST have a deep sand bed on top of the plenum to create the no oxygen area called the plenum. A DSB will do the same thing just without the need to build the plenum. That is the joy of both systems-less maintainence. All the critters that live in the sand beds do all the work for us. No need for stirring, vacuuming, or cleaning. If you are interested in using either system, I suggest you read as much as you can on both DSB and Plenum systems. This will give you a better idea of what will be beneficial for your tank. I am running a DSB on my tank that is 5" thick and my nitrates are zero and have an abundance of critters moving around in the sand. Never had to clean it at all. HTH--Bob

 

[sundog]

The main benefit of a plenum (and I'm not stating this to start another debate about DSB's vs. Plenums) is that a plenum system requires less sand and the grid that seperates the lower layer from the rest (if correctly installed) keeps the lower layer from being disturbed.
A deep sand bed will do the same thing as a plenum, however with a DSB you need at least 1 to 2 more inches of sand (more cost, especially in a BIG tank) and there is a slight risk of sand creatures disturbing the lower layer of sand (which you want to avoid) and the plenum, when correctly installed, will prevent that.
They BOTH are great and I would go with either one, rather than neither, as your tank should be more self-sustaining and healthy with either of them.
[ April 19, 2001: Message edited by: Sundog ]

 

[burnnspy]

Sorry Bobber, but a correction is in order. Plenums have no oxygen free areas, only O2 poor. DSB have O2 free areas.
Sundog is correct in that Plenums are cheaper due to a need for less sand, nor do plenums require sand sifters as DBS do(even less money).
I run a plenum in my 29gal reef with 3.5" of LS over the plenum and have maintained zero nitrates and don't have sand critters.
For more Info on Plenums read Live Sand Secrets by Dr Bob Goemans ($7.00)
BurnNSpy

 

[saltwaterking]

Good Book and a pulem is the only way to go! I have one in my 38 gallon and one in my 40 gallon breader and there both reefs.

 

[gnelson]

Recently many studies have proven that a plenum may not be the way to go. Although they may be a little cheaper, after investing $1000's into everything else why not shell out the money for a few more pounds of sand and some stirring creatures. There is a good chance that after a while a plenum system is going to leach many of the undesirable nutrients back into the system. Such as nitrates, phosphates, and silicates. In my opinion a DSB is more reliable and safer.
Graham

 

[bobber]

That's okay Burn. I'd rather be corrected than give false infomation. But I could of sworn that the plenum would create an o2 free zone. Maybe just a brain fart! Thanx for the correction. --Bob

 

[sonny]

Just to clarify, a plenum system does not accumulate nitrates, phospates or silicates any more than one with a DSB. In both systems, the nitrates are reduced to nitrogen gas and released into the air. Phosphates and silicates are put into the system with low quality source water or foods, and will continue to rise until you get better source water or better food. They can be removed with good carbon or element sponges. The plenum helps the water to circulate through the sand bed very slowly. In a DSB, there is very little to no circulation. This circulation is called "diffusion." Both systems work, and it is a matter of personal preference.
Good luck,
Sonny

 

[tnreef]

Gotta agree with Sonny on this one. Both will accomplish the same thing. LOW TRATES!!!
I go with a DSB it was easier. LOL
IMO Darryl

 

[invertman]

I set up my 2 plenum tanks 7 years ago and they are still going strong. No nitates and no sand stirers. I am not saying this is the ultimate set up. I am still waiting to learn what that is. Burn is right, plenums work and they are easy.

 

[burnnspy]

Originally posted by TNReef:
<STRONG>Gotta agree with Sonny on this one. Both will accomplish the same thing. LOW TRATES!!!
I go with a DSB it was easier. LOL
IMO Darryl</STRONG>
What do you mean by easy TnReef?
It took me less than a hour to make my plenum.
I do no maintenance to the gravel.
How is a DSB easier, since you must have sand stirrers and such. DSB if done incorrectly generate Hydrogen Sulfide with the potential to wipe the reef. When a Plenum is done wrong you have an UGF and maybe some nitrates.
BurnNSpy

 

[diatom]

Just at add a little twist. Has anyone tried Cell-Pore as the basis for your plenum? If so how does it work? I've heard that there is a scrren you can use to seperate your sand from the Cell-Pore, but it would have to be very fine indeed to keep suger sand from settling into the open space ruining your plenum I would think.
Any ideas?

 

[burnnspy]

I dont know anything about Cellpore, but i do know a plenum will not work as it should with sugar sand. I recommend Seaflor reef aragonite gravel.
BurnNSpy

 

[tnreef]

Easier in the fact of the setting up in an existing tank. Sand stirrers were already part of my tank at the time and not a concern. As for sulfide in my OPINION it is not an issue WITH THE ADDITION OF ENOUGH SAND STIRRING CRITTERS. It allows the release over time. Just my opinion. I am not going to start a debate. My next tank (135 gal) will be running both plenum (due to the fact it will be a new tank)AND refugium.