Will this RDSB idea work?

[LobsterOfJustice]

Hey everyone,

I'm fighting a bit of a nitrate problem. In addition to cutting back feeding and doing some large water changes, I'm thinking of installing a remote deep sandbed. I have a frag tank attached to my system, but I dont want to have the DSB in the actual tank. I have half a 5g bucket of sand, and I am thinking of cutting the top half of the bucket off and just sitting the bottom half of the bucket with the sand in the frag tank. I figure this is removable, accessible, etc. Can anyone see a problem with this? I figure it's essentially a RDSB in a bucket like many others have, except the bucket is sitting submerged in my frag tank.

[CleveYank]

Ahhh???

I have 90 gallon with 6 inch DSB.
That's 48 by 18 by 6 or 22 gallons of water displaced by sandbed.

For a 90, for an established reef tank with a decent bioload I would not see how 50 to 65 pounds of livesand in a 5 gallon bucket would do much good. IT's not to say that it would not have any impact.

A concern I might wonder about, wouldn't there be a point of going from low to zero O2 content like deep down towards the bottom of the 5 gallon bucket? And isn't there a limit on the impact of surface area in relation to the rest of your setup? Size and gallons? On the onset it seems like a good idea. But with limited ability to interact with the water column can it really do alot of good other than leaving it possible for a making a deadspot that could produce harmful hydrogen sulphide?

http://reefkeeping.com/issues/2005-12/rhf/index.php

Not so sure about that idea.

Now if you kept it around 6 to 8 inches deep and put some tubs or buckets you could remove that sit underneath your frag racks on the entire bottom then you might get the best benefit and have a prevention of leading to a major deadspot or possible hydrogen sulphide bomb.

[LobsterOfJustice]

You mention the worry of the deeper areas lacking O2... isn't that the point? The bacteria which break down the nitrate live in areas with no oxygen.

The lack of surface area is something I would like to get more opinions about though. I'm wondering if this is even going to be worth it with 150g worth of water in the system.

FWIW, I just went and measured. I have 7" deep of sand in a bucket that is 13" in diameter.

[Pmolan]

I always thought you wanted the lack of O2. I also keep reading that RDSB's should be 6-8" deep. If you have it designed to be removable then I say go for it. If it doesnt work then dump it in the yard and let your kid play in it. I think that you will have exports from different things adding to zero nitrates. Fuge, chaeto, rdsb. One may not do it all, but all 3 might.

[King-Kong]

Lobster; why not just go the normal route, and use the bucket w/ bulk heads? You get more depth (mines at like 10"), and it's just as easy to remove.

[CleveYank]

wow...my skim reading is way off...lol or my speed reading skills must be rusty.
I missed the cut the bucket in half part completely.
Me thought you said 5 gallon bucket IE have a 5 gallon bucket full of 14 inches of sand...which would be too much of a low oxygen area.
At half you are right in there.

I still wonder how much good that little bit of sand will do in a well stocked 90. I mean you are talking 7 inches of sand in 13 inches diameter.

If we keep it simple. My 90 has 22 gallons worth of sandbed. Your 90 with the cut in half 5 gallon bucket is going to be about 2.5 gallons of sandbed right? Your mobile 1/2 5 gallon bucket sandbed is 11.5 percent of what mine is. I have 250 pounds of liverock. 60 hermits and 80 plus snails. 1 fish. And 30 large SPS frags/corals and 60 small/med frags. I feed the tank every day. And since there is a sun coral I tend to feed rather heavy on alternating days. I have 6 clams in the tank. I have a barely adequate skimmer on it. My nitrates at last testing were undetectable with cheap testkit. My phosphates were undetectable. I have no algae problem. I have had that deep sandbed in my tank since 98' I have never had massive algae issues in this tank since going to the DSB. You can try the small amount in 1/2 a bucket. But I don't think that it is going to do enough or at least help your 90 in the amount that you think.

And Pmolan is right about multi approach and that if it doesn't work you can just toss the sand into the yard.

Sorry for the misdirection...lol

[LobsterOfJustice]

Kong, two reasons, both of them involve being cheap and lazy. This is all the spare sand I have sitting around, so this way I dont have to buy more. And secondly its just easier... I figure I already have the space in the frag tank... Why not use it instead of adding even more plumbing etc to the system. If you think it would make that much of a difference I can do the usual way.

Cleve, I think the difference is you are using your DSB as the main filtration and a skimmer which you mention as "barely adequate". I'm basically the other way around... the skimmer and filter socks are my main filtration, with this barely adequate DSB to pick up the leftovers.

Honestly, I probably wont even use it long term. If i can just get it to soak up all the nitrates, I'm probably not going to just leave it in there, I'm going to yank it (and all the nitrates) out.

[Icefire]

try it

[King-Kong]

Originally posted by Icefire
try it

Agreed.

give it ~4-6 weeks, and if 'trates dont drop, it's probably not working.

[clekchau]

interesting idea, it 'should' work if there is enough flow going over the sand. try it and let us know.

[LobsterOfJustice]

Alright, I'm putting it in today.

[LobsterOfJustice]

This is what I ended up with... I had to add some extra powerheads to make sure the corner behind the bucket didn't become a detritus trap:





Oh and this

[Pmolan]

Wow.. What the heck is all that crap on your fan? Is that suff airborne?

[LobsterOfJustice]

Apparently. The fans just gunk up like that after a few months. When they start to slow down or make a noise I just rinse the whole thing out under the tub faucet. I just did it this morning to the fan on my canopy actually.

I blame the girlfriend's cats.