Tank Bottom. Will this work?

[Aqua Keepers]

<a href=showthread.php?s=&postid=15516544#post15516544 target=_blank>Originally posted</a> by KarlBob
AquaKeepers - You could be right. I'm a softies/LPS guy, without much experience of hardcore SPS tanks.

Santoki, your tile picture gave me another idea for a "faux sandbed" project:

1) Cut tiles as needed to fit the entire bottom of your tank.
2) Spread reef-safe glue over the tiles. Cyanoacrylate should work, but may set too quickly to be practical. If you're patient, try silicone.
3) Pour sand/crushed coral/etc. over the glue.
4) After the glue dries, shake off the excess sand and place tiles in tank.

With multiple layers of tile, and silicone to smooth out the transitions, you could probably make pretty convincing "hills", if desired. Tiles and glue/silicone aren't likely to detach from the bottom and float up, no matter how long they're in the tank.

In time, this will get covered with Coraline as well.

 

[Santoki]

The point I'm trying to address is that no matter what you put on the bottom, it will eventually get covered with coralline. If you want to make hills on the bottom, you might as well just cover the glass bottom with some type of quickset cement and shape as needed. No need to put tiles in first. The only reason I used tiles was that they had a rough surface which makes it more hospitable for encrusting organisms, and in the case of any rock slides, it would provide some sort of protection for the glass bottom.

 

[tasos]

I did the same thing with the silicon and crashed coral.The result is that the coral pieces dettached from the silicon easilly, and I can see the silicon now.Also another dissadvantage is that there is always some dirt accumulating in the substrate, but in the case of the crashed coral it is there to see it.With the shallow sand bed it is hiding beneath the sand.
I am happy to can blow the detritus from the thin layer of crashed coral with a powerhead.It is going to the sump with a good flow from the overflow, so I can siphon it with water changes .
Last, coralline algae is covering everything that cannot move as the sand does!!

 

[KarlBob]

I agree that if you have sand grains attached to anything, they will eventually get covered with coralline. Anything that does not move, and has a texture that coralline can hang onto, will eventually get covered. The only way to permanently maintain a sandy-textured, sand-colored bottom is to have a sand bed.

The OP wanted to do an entire tank bottom sculpted of GS. It was pointed out that the GS would eventually detach from the glass and float to the surface. I saw the tile picture, and thought that tile would be a good, non-floating base for superglue and sand. I suppose you could skip the tile, spread superglue directly on the bottom of the tank, then pour sand over it before it dried.

It's true that quick-setting cement would probably be closest to the OP's original idea, because you can sculpt it the same way you would sculpt GS. As a bonus, cement that hasn't been smoothed often has a sandy texture. Sculpting the tank bottom from quick-setting cement would eventually result in the bottom of the tank being sand-textured, but coralline-colored.

The only reason sand beds don't turn coralline-colored is because the individual grains of sand can move. Sand grains frequently turn different faces to the light, scrape against each other, and scrape against other things (live rock, the walls of the tank, etc.). All of these events discourage or remove coralline, and none of them would happen if the sand grains couldn't move.