Bare Bottom and Sand Bed Combo?

[RobbW]

Okay, I'm brainstorming how I want to layout my tank when I do my substrate change-out and re-scaping in the next two weeks. I prefer the look of a sand bed in the tank. I just think it looks more natural with sand. However, I really like the concept and principals behind running a bare-bottom tank. So, now I'm wondering about the feasibility of combining the two.

I plan on using eggcrate to lift and hold my live rock over my sand. What I'm thinking of doing is using bent acrylic strips (or some other type of material that can be formed) siliconed to my tank bottom to separate my sand from a BB area directly under my rocks. This barrier would probably be about 2" high and would keep my sand in the front of the tank and the back of the tank under my rocks as a BB area. I would use this barrier and pieces of pvc pipe cut to 2" as stands for the eggcrate. My LR would be stacked on the eggcrate. I would direct the return from my sump down under the eggcrate and terminate it with a spray bar that would run the length of the back of the tank in the BB area. I used my cr@ppy Google SketchUp skills to mock up a preliminary drawing. I will attach it as a jpg to this post.

The tan area in the front of the tank would be a 1.5-2" deep sand bed. The blue area behind would be the BB area. And the thin green thing would be the spray bar connected to the sump return.

Does this sound feasible? Does anyone think it's a good idea? Any suggestions on improvements?

[VWD]

I don't think you will be able to keep the sand where you want it, it will be harder to keep the detritus from building up under the rock on the BB side, You will have to watch the amount of flow you have. It may work for alittle while, but I think you will end up with a sand bed in the end.

[wharyat]

I've seen that same thing done before. I think the guy had the same problems that Vinnie brought up.

[RobbW]

Valid points. I guess I got too excited about this possible design before I really thought it through. I'm trying to figure out a way to have a sand bed in my tank, have my rocks lifted, AND be able to keep the area under the rocks clean. I seems quite challenging to have a full sand bed under lifted rocks and be able to keep it clean of detritus. You can't direct too much flow under the rocks because it will just blow sand all over your tank.

[fihsboy]

Buy tan starboard and go without sand. Then its bare bottom.......but the bottom is still tan like sand would be.

[wharyat]

The problem with any static bottom is that eventually coralline will cover it.

[RobbW]

Yeah, but then how do you keep the starboard looking like sand? It's just going to encrust with coralline over time, right?

Is it necessary to have a bottom/substrate at all? What if I used a sheet of eggcrate that is the same dimensions as the bottom of my tank, lifted it about 1", and then just covered the entire eggcrate with LR and LR rubble? There would be no open substrate or bottom, just LR. I'd use flat pieces of LR towards the front of the tank and then slope up towards the back. I could put a spray bar from the return under the eggcrate in the back blowing forward.

Actually, I'd probably cut the eggcrate slightly narrower than my tank so that I could glue small pieces of LR rubble along the edges to camouflage it.

[wharyat]

You don't need any covering at all. Just glass works great.

That sounds like a cool system. It's sort of like a plenum, but with potentially better filtration.

[Elegance Coral]

I like the idea. You may not be able to keep ALL the sand out of the back compartment, but it would be better than just piling up sand under the rocks that you can't get to. I don't see a great deal of sand getting back there unless you get a sand sifting goby or something like that. I run all my Elegance coral tanks with spray bars behind the rocks. This allows me to circulate a good amount of water without blasting the corals will to much flow. It also keeps the area under the rocks pretty clean.

[RobbW]

Since I first started this thread, I have decided to upgrade from my 30G to a 55G. This may change the original design for a BB/SB combo. Most importantly, the spray bar would need to be longer. Using a Mag 7 pump with about 5 feet of head to lift, what's the longest spray bar I could use without totally diluting my return flow? Also, there's a tank pic out there I found that is inspiring the way I want to scape my tank. In order to emulate it, I will have to create two LR islands with the sand bed going all the way to the back glass in the middle. This would require splitting off the return into two separate spray bars under each island. How will this affect my flow?

[RobbW]

meh, screw it! I've been cut off from spending any more money on this tank. So, I won't be able to buy all the plumbing and accessories necessary to make this work anyway. I'm just going to stick with a full sand bed, lifted rocks (I should be able to sneak a couple more bucks for a short piece of PVC and some eggcrate), and the normal over-the-back return.

Oh well, it would have been fun to try.