# Rock questions



## carboncopy (Jul 26, 2009)

Well I have the tank almost ready to go, I just need to get some rocks to create some caves etc for the cichlids to hang out in.. It is a 47Gal bowfront tank, so nearly 2' in height that I need to try and include. In order to do this, I would need to stack some rock to get the height. I was looking at some very porous rock that is fairly light, but started wondering how to clean algae off of that if it builds up? If I use regular rock, it could get quite heavy.

Any suggestions?


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## JIM (May 27, 2009)

*For a setup with rocks stacked that high, youre gonna have to build it essentially like you would a reef in a salt tank. Start on the bare bottom of the tank for stability and build it out at the bottom and tapered as it goes up. I would use some flat pieces to create shelves and hang overs for caves, about any kind of rock you use will be heavy in total, if you want it to stand up forever. But holey rock will be somewhat lighter, as for algae, do the things needed to keep algae at a minimum, and that wont be an issue, and a little algae isnt bad, IMHO, it adds to the overall natural appearance of the setup. You ever seen a pristine lake or pond with no algae growth?? *


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## carboncopy (Jul 26, 2009)

So what is a realistic weight that I can put in this tank spread out over about 1/3 (or a bit less) of the tempered glass bottom? I do not know the actual thickness of the glass, but I likely have 30lb worth of sand in it now...


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## JIM (May 27, 2009)

*Ive never heard of a load limit on a tank that is setting on a solid, flat foundation, by that i mean supported completely underneath and not just like most stands where the bottom is partially open *, *If its setting on a solid base and the rock is resting flat on the bottom, i dont think you could put enough in to be a problem, unless you tamped it in with something and the outward pressure caused it to expand and break.*


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## carboncopy (Jul 26, 2009)

It is a standard tank, so the bottom is about a 1/2" up from the stand. Is there a common way to support the bottom for this purpose? Cutting something would require a lot of precision which I could not gurantee. I would hate to use something that would end up being just a bit high, and stress the glass that way either..


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## Oldman (May 25, 2009)

The best way to ensure that you don't have any concentrated pressure in a small area is to use the sand or gravel to spread the weight and even to use something like the egg crate they make for light diffusers to really spread the load. I must agree that without spreading the weight of rocks, your tank bottom will be threatened by locally high stresses.


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## carboncopy (Jul 26, 2009)

Well, I got the tank up and running.. There is about 30lbs of sand, 30 lbs of lace rock, and 10 - 15 lbs of lava rock and no leaks or broken glass. I read somewhere that as long as the glass isn't hit, and the weight is more or less distributed you could fill the tank with rocks. Don't know how I feel about that answer but it was a bit reassuring.


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## jbrianchamberlin (Aug 31, 2009)

Looks very nice...


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## MutedMonkfish (Jul 4, 2009)

Nice setup.Plain and simple


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## JIM (May 27, 2009)

*Looks great to me , i dont see anything that would cause an overload problem, you should be fine *


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## Oldman (May 25, 2009)

I really like the look you have achieved Carboncopy. The volcanic rock is also nice and light and should not pose a threat to your tank. The flat rocks, by their orientation in the design should also distribute their weight over nice large areas.


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## carboncopy (Jul 26, 2009)

I am quite happy with it, and the fish seem to be enjoying it. The one cichlid (I thought it was a kenyi, but may be mistaken) has really gone to diggging, and has himself a nice little cave under the very bottom middle lace rock. I have been trying to keep an eye on him though so he does not get too much dug out, and squish himself. Also once i get a chance I will have to post up a pic of this fish to determine if he is in fact a kenyi or not.

Thanks for the help and feedback.

cc


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