NNR and Jaubert/Plenums?

baloo6969

baloo6969

Member
Ok I’ve read 3 books so far, and when they discuss Nitrate reduction, they mention Plenums and Natural Nitrate Reduction methods, normally only 1 paragraph in each book, and all it says is “it’s experimental”…basically the idea is to take a fuge, put a horizontal raised level grate on PVC pipes as legs, that leaves a pocket in the bottom, and 2 inchs around the edges of the glass. Lay a screen over it. Put ~2 inch of LS on it. Then another screen over it, put some CC on it, then another layer of LS on it…Inevitably leaving a DSB with layers.
The idea is to leave a gap of air under the sand for denitrating bacteria to grow…I think.
Has anyone done it? Or heard of it?
 
T

tizzo

Guest
Way back when I first started my tank, I considered the plenum. Then somebody pointed out to me that If I had a rock tumble it would upset the "chemistry" of the tank to the point that I could lose the entire tank. The plenum would work, but it's balancing on a high wire...
So I abandoned the thought... My tank has been set up for years and I have never had trates. Just learn where they come from and avoid them. You do not need a plenum for that.
 
baloo6969

baloo6969

Member
Originally Posted by Tizzo
Way back when I first started my tank, I considered the plenum. Then somebody pointed out to me that If I had a rock tumble it would upset the "chemistry" of the tank to the point that I could lose the entire tank. The plenum would work, but it's balancing on a high wire...
So I abandoned the thought... My tank has been set up for years and I have never had trates. Just learn where they come from and avoid them. You do not need a plenum for that.

yes, but if the plenum was in a fuge with little or no rock, how could there be an upset in the chemestry of it?
 
baloo6969

baloo6969

Member
Originally Posted by 1journeyman
As I understand it a deep sand bed works the same way but is easier.
well i think that if you leave a stagnant pocket of air under the sand it wont work the same as a DSB...it will either work better or cause more issues.
and as far as "ease" of setup...how hard is it to cut a piece of eggcrate, take 2 pieces of PVC pipe and tie wrap them to the egg crate, then lay a fiberglass screen over it? Probably take 15 mins extra; apposed to just dumping a bag of sand in.
Originally Posted by larryndana
so your thinking of putting a plenum into a fuge. Interesting....for sure..
Yes, i think it will allow for a good amount of "even flow" over the sand, little or no sand disturbance (hence why i asked about critters digging)
 
althemean

althemean

New Member
there is a big article on plenums in marine fish and reef magazine (I think its that one) in this months issue.
They discuss a long term experiment done with a plenum in the Waikiki aquarium. All parameters were monitered for 3 years by the university of Hawaii. They claim a fairly stable set-up was achieved. It had its ups and downs as with any system. They also say when disassembled, the sand bed was alot cleaner than a DSB alone.
Interesting read. Also, with the plenum, it was required to seal the edges so no substrate seeped into the plenum water.
 
baloo6969

baloo6969

Member
I don’t get that mag...Cant find it anywhere.
Humm, how could i get a *pocket* under the substrate? Maybe take 2 pieces of egg crate, separate them with PVC, then wrap them in fiberglass screen maybe? (Make a burger out of them wrapped up like at Burger king)
 
althemean

althemean

New Member
I picked it up at Petsmart....while I was buying some toys for our cats. They get a little jealous of the fish tank.
 
txmedic1

txmedic1

Member
your right, this months marine fish magazine (petsmart) has a huge article on plenums. i believe it said its kind of old skool.
 
althemean

althemean

New Member
I honestly fail to see much of a difference between a plenum and undergravel filter. The only real distinction is the larger space in the plenum vs undergravel filter. Plenums also do not use the riser tube (GARF does for a few weeks then caps it off)
There are so many ways to achieve the same result. Diligence with any one system is likely to provide satisfactory results.
If you are attracted to the idea, do it. The worst that happens is you tear it down and start over and waste some time. (hopefully not killing anything is the key) It would be best to have a second tank setup ready to accept the LR, fish or whatever you have just in case the plenum experiment crashes.
I dont have the experience to say what works and does not. I am just making the transition to SW after a long absence from FW....
 
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