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Plenum System Question


O. vulgaris
Oct 19, 2005
Hello :smile:

First of all this isnt an octo tank question, its for my main reef tank. I'm just trying to get a variety of answers and you guys are so helpful! :smile:

I have a 150G. setup thats been running for quite some time now, its a very mature tank.

Since day 1 I have been running a reverse flow undergravel filter, a canister filter, a skimmer and tons of live rock. So lots of filtration in the tank.

I was wondering how it would effect the tank if I removed the undergravel filter tubes. Just like a plenum it would create a dead space under the substrate. The idea is that the dead space helps in the denitrifying process.

Will this work in my setup? Does anyone have experience with Plenum systems ? :smile:

Any responses very much appreciated! Thank you.
Octos are said to be adept at discovering undergravel filters, pulling them up and making them their homes.

I've never tried one, but I think that a plenum probably isn't the best way to get NNR. If you think about how the process occurs in nature, this reduction happens because of microbes that like to live in substrate and not open water--hence why people use deep sand beds. Now given that, DSBs aren't usually recommended for octo tanks either.

This is for my reef tank so I dont have to worry about an octo tearing up the filter.

I'd really like to get rid of those raiser tubes :nyah: but before I do it I'd like to be sure that it wont wreak havic on the enviroment.
If its for a reef I'd say go with a deep sand bed. Don't take my word for it because there are those who believe it will destroy your system :smile:

Loads of arguments over that dsb timebomb thing. If you have it in the fuge you can clean the sand out every year or something, and you wont have the brown dirty sand that many people get. I think a popular trend is a 1/2 inch sand bed at the front with a bb and sprey bars at the back, meaning you get the look of sand, but without the crud build up.

Remember if you wanna run zeovit or similar you cant have a dsb(from memory), however both will give good colours to sps corals.
I guess I'll just play it safe and leave it like it is :nyah:

Not too sure I really have options, the tank is fully mature and established and pulling out those undergravel plates would probly be classified as messing with the system a little bit too much. I've heard of alot of people running plenums for reefs for years and years, but I dont really understand the pros and cons of it.
I think a plenum is one of the older-school ideas. I dont think people who are setting up new tanks generally use them.
But if it might destroy your system it isnt worth removing, especially since it doesnt sound like your having any problems.

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