For those of you with bare bottom reef tanks

[Chin_Lee]

Do you guys put your rocks directly on the glass or are they lifted off the glass? I am trying to decide whether to make argocrete rocks with "table legs" to act like platforms and then pile the rocks on the platforms or pile the rocks directly on the glass? What are the pros and cons to both?

Secondly does the bottom gets covered with various algaes and polyps in time? If so how long?

CWLee

[LostMind]

Well, I think the point of the barebottom was the ability to remove detritus easily - whereas the sandbed in theory, traps all the detritus. Also to increase flow in the tank...

So while I think cultivating a bed of gsp or polyps would look cool, it would defeat the purpose of the barebottom tank by trapping the detritus, or at least making the removal of it hard.

I believe most people are against putting the rocks directly against the glass. Some people raise the rocks with acrylic rods, others use PVC and others put something like eggcrate or starboard underneath the rocks to prevent direct contact with the glass.

[Quinn]

I certainly wouldn't try to put rocks on "table legs". Even though the rock are much lighter in water than they are in air, you wouldn't want to have all that weight pushing down on a small area.

[IslandReefer]

Good point Quinn! ("on the table legs")
Another idea that looks good at first blush....of course I was going to do this, but now, on to plan B;
I was experimenting with "acrocrete"(sp?)(produced several "good" tables) and found that if you mold on top of milk carton paper etc the bottom of the artificial base rock is very shiny , smooth and flat, therefore shouldn't scratch or place uneven pressure on the bottom glass. Putting eggcrate down first (whats starboard?...around here thats the right side-o-the boat) might still be good in that it would ,be lighter and could be made to not displace a lot of the sand bed. I was thinking apx 6inch strips (2x drill bit length) eggcrate with some 1/4 inch holes drilled through to allow sand, worms,O2,H20 to flow under the LR without destablizing everything.
On top of this I was thinking of using custom acrocrete bases on the eggcrate. by making the base rock 3-4 inches high 1/2 to 1inch sticks up above the sand, upon this goes the live rock( ...think $5-10 per lb). Using a masonary drill mounting holes can easily be placed to attach the LR with the "live" part out of the sand and in the light.
Also by " whipping" the acrocrete you can make it very light and porous .
So...what do yous all think?....workable?.....on to plan"C"?
John

[Doug]

My tank is a custom made, with no black frame on it, just glass tank. So first, it sits on a complete sheet of 1in. styrofoam.

Now that being said, all my base rock sits direct on the glass. They are large flat bottom pieces. The reef is then built up from there. I do have a mixture of crushed coral and fine sandbed in the back half of the tank, but the rock was in first. Perhaps some pieces are sitting on the sand as bit from re-construction projects.

The front half is bare bottom, {sand wise} a covered mostly in rubble. Its kept pretty clean by the Tunze pumps. I have some thick coralline growing on the bottom and many mushrooms in the rubble but no polyps.

Forgot to mention, my glass is 5/8th.