Plenum with drain

[el chupacabra]

I'm thinking of getting a plenum because I heard that plenums act as a nutrient sink. Whether they do or don't, it makes sense to me that over time both a plenum or dsb would become a sink. so I was considering drilling a hole/drain underneath the plenum and using that hole to drain the tank 20% every 2 weeks during water changes. I don't know if this has been done before but I can't do a search here...

The idea is any bad stuff that accumulated at the bottom of the tank could easily be flushed out. water would flow through the sand during drainage and wash stuff to the drain, thus cleaning out the sand bed every 2 weeks.

I realize the plenum would become oxygenated during water changes but don't think it would be that big a problem.

I currently have a dsb and it's obvious most people like this method better. But Usually most people change out their dsb about once a year. This can be a pain. So I figured I would just have a 3''-4'' deep sand bed over the plenum and all I'd have to do is stir it up every now and then.

It seems to me theres really too much diversity in how people take care of their tanks to debate if nutrient sinks are a problem with dsb to much. I'm just wondering if anyone thinks this might be a good idea to take advantage of a nutrient sink if one exists...or maybe I'm missing something really obvious here.

 

[Fatboy]

Hope this helps....... http://www.reefcentral.com/forums/showthread.php?s=&threadid=673910

By the way, yesterday I change my tank for a new one and I had to disssemble the plenum that I run for almost 4 years. You wouldn't believe how much junk it was in there.....

 

[el chupacabra]

Thanks for that link it is very helpful.

Since you just changed a plenum could you just tell me a few things.
How deep was your sand bed?
Was the junk just inside the plenum or in the sand above it? How dirty would you say the sand was that was immediatly above the plenum? Very very dirty, just dirty or fairly clean?

I was thinking I could put a algea cleaning magnet under the plenum to use during water changes. If the sand above the plenum is very dirty though then it wont work.

 

[Daemonfly]

There's also the older "Controlled Plenum Wasting" thread

http://reefcentral.com/forums/showthread.php?s=&threadid=289910

 

[Cody Ray]

I think that you could accidentally expose that area to oxygen which could really damage the anaerobic bacteria. This is why I like the upsidedown sandbed idea. The sandbed (which is roughly 10 inches deep) is suspended above a plenum-like structure. There is a tube that runs from the plenum to the surface. Water is pumped into the plenum and exits through the tube to the surface. By doing this you double the surface area of the sandbed while preventing detritus from building up. The anaerobic area develops in the middle of the sandbed.