Rock placement... directly on bottom glass?

The books I've read say that it's best to place the rock directly on the glass before adding the substrate, so that sand-sifting creatures don't undermine the substrate beneath the rock and cause a tumble.

1) I'm worried a little about pressure points from the rock causing a breakage. I dunno... it just seems dangerous to place jagged rocks directly on glass. Of course, I realize that if this really were a problem, there'd be stories all over the place of broken tanks.

2) I'd like to fill the tank this weekend, and have the sand and dry rock in place to begin cycling (live rock will be added in a few weeks, once I've decided where to get it from). However, I wouldn't consider any rock placement right now to be permanent... I'll likely want to move things around once the live rock arrives. So, I guess my question is this... can I add the sand, place the rocks loosely on top, fill the tank, then later (when the LR arrives and I'm ready to aquascape for real), place the rock where I want it, wiggling the bottom rocks back and forth to dig them into the sand so that they are touching (or very near) the bottom? My sand bed is only going to be 1.5 - 2 inches.

--Mike

wastememphis said:

I have my rocks on the glass, with no substrate. So you'd be fine if you did it then put substrate in.

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Actually, I want to do the opposite... put the substrate in, and put the rocks in position later. I can't think of any reason why I couldn't do this (like I said before, just scooting the rocks back and forth to dig them down into the sand so their not just sitting on the surface).

Sorry, I guess it's one of those dumb questions that shouldn't need to be asked... I just don't want to be in the aquascaping phase (after the substrate is in and tank is filled) only to find that it's an absolute necessity to put the rock in first. I mean, people change around their rockwork from time to time, and I imagine they don't remove the substrate (to get the rocks resting on the bottom glass), correct?

--Mike

LittlePuff said:

Is it FOWLR? If so, you could get the starboard, forget the sand and the clean up crew. It would depend on which fish you want, though.

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Yes, it will be FOWLR... but I WANT the cleanup crew (and sand). I find snails, crabs, shrimp, etc., just about as interesting as the fish!

--Mike

Decz said:

my rocks don't sit directly on the glass- but they do come pretty close!
I put my substrate in and dug the big rocks in... IMO this gives more stability, but doesn't force you to put the rocks right on the glass. Just use your hands to shift the sand around... beware tho, that it'll take a few days for the dust to settle.

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Thanks... I decided to go ahead and proceed this way. The sand is in, and the tank is filling. It's extremely cloudy now (see this thread for photos), and I guess that even after it settles, I can expect a relapse when I put the rock in place.

--Mike