Plenum size for a 90gal/Fish only

[Nocturnal]

Hello,
This is my first post and had no idea where to put this question so here it is:
I am setting up a 90 gallon fish only tank and have decided to go the plenum route instead of my trusty wet/dry. I will be setting up a sump and I have a 20 gallon "long" (30x12x12) available to me. I guess I could also buy a 30 gallon long if I needed to.
Question is: how large should my plenum be? The tank will be fairly well stocked. Will the 20 handle it? I was thinking of a 1" height for the plenum?
Any help would be greatly appreciated.
TIA

 

[danmhippo]

Any chance you would want to redo the main tank and incorporate the plenum in there instead? The screen and eggcrate used for plenum should prevent your fish disturbing the layers down below anyway. You could first setup the 2 smaller tanks, and move your fishes to those 2 temp tanks first while you work on the main tank.

 

[ReefLion]

Out of curiosity, any particular reason you decided on a plenum as opposed to a deep sand bed?

Tim

 

[Nocturnal]

I didn't want a DSB mainly because from what I understand it relies heavily on detritivores and I really didn't want to be adding little creatures to my sump. I may in fact just try and put one in the tank, but also wanted to stay away from a giant sea bed 4" high. I wanted a thin layer of sand in the tank and a sump with my filter out of the tank. Am I wrong in thinking a DSB needs small creatures to keep things moving down there? If so, then I may just get a large rubbermaid conatainer and make o sump out of that.
All ideas are welcome...
Also, the main tank is drilled through the botton which makes making something inside the tak such as a plenum more difficult, but still easliy accomplished.

TIA

 

[Bryan Thompson]

Dan is right. Put the plenum in the main tank. Get ready for everyone to start the flames about the plenum. I use one and they work great. Better than the deep sand bed in my opinion.

You can use the support structure for the plenum as an anchor for rock platforms to increase your exposed sand bed area and decrease the amount of live rock you need.

Here is a shot of mine.

Bryan

 

[ReefLion]

Many people have success with both DSB's and plenums, but the former are much easier to set up. Yes you have little creatures, but they come with the rock anyway.

You can set up a DSB in a sump, and just put any amount of sand in the display tank to suit your visual tastes. That describes my system exactly (4" or so in sump, and about an inch in the display).

Go with what you want, but a few searches on this board for "deep sand bed," "DSB," and "plenum" could be useful in evaluating options if you haven't done that already.

Tim

 

[Nelliereefster]

Plenum!. Go to www.thereefweb.com to the DYI section. Good pics and instructions and.....

God bless you, plenum loyalist

 

[danmhippo]

I have nothing against plenum other than it's a pain in the ass to setup. I have a plenum in my system as well, not that I favor it over DSB, but just I am too lazy to tear up an established system just to incorporate DSB into the main tank. Instead, I setup 2 refugium in the cabinet with 5" DSB.

However, your expectation of an inch of plenum may not be that possible. When I setup mine, I have 3/4" of empty space at the bottom with sections of 1/2" PVC's, then eggcrates, screens, layer of sand, another screen and another inch of sand above. 2" or more is a more realistic number to work with though.

 

[Nocturnal]

Well, building/setting up a plenum is no prob. I build cars in my part time, so this is like playing with legos. I built it last night. It stands 1.5" tall so i'm in for a deep bed, oh well. I figured out a way to hide it

Now for mechanical filtration I have a bunch of lifeguard filters lying around. Question now is, should I use them or just plumb in a sump to house anything extra I need?

Thanks for all the great advice guys!!