how many rocks can a 90gal support

[valerie]

I"m building some rock caves in my 90gal and was wondering how much weight the bottom glass can hold? I'm using granite and its quite heavy and don't want to have any problems down the road with wieght issues. I already will be using 100pounds of gravel,how much rock do you think it can take?

[wetmanNY]

Before you put a grain of gravel in your tank, lay a cut-to-size grid of light-diffuser "eggcrate" on the bottom glass. This will distribute the weight of your rockpile. Otherwise, all that weight will rest on three points!

After all the rocks are in place, then add sand. You don't want a cave supported on sand.

[valerie]

yes i plan to add the egg crate to distribute the weight. So how much rock can i add? I"m not going to be making a rock wall from top to bottom,just about enough to go maybe half way. Will the weight be a concern or can the bottom support lots,so it won't be a problem?

[GDominy]

I have 150 lbs of Slate in my tank, along with 200lbs of gravel. I'm not using anything on the bottom glass to distribute the weight except for a very thin layer of gravel (.25 to .5 of an inch).

http://aquafiend.plantedtank.net/images/Nov2202/135.jpg

[Richer]

http://showcase.aquatic-gardeners.org/2001.cgi?&op=showcase&category=1&vol=-1&id=44

Not exactly a 90 gallon tank, but if this 180 gallon tank can support that many rocks, I'm sure your 90 gallon can do support a proportional amount of rock as well.

HTH
-Richer

[keely]

You might want to ask on a reef board... those dudes (and gals) pile rocks in there like there's no tomorrow.

[Hatter]

I have over 100lbs of granite in a 75g which is the same size. I think you'll be fine.

I do however think your going to have too much gravel. If I remember right, I used about 60-70lbs when I set mine up. But I guess you could be using a different size...

[valerie]

Thanks for all the replies. I guess the amount of rocks i'm thinking of using will be ok.

About the gravel I don't know if i'm going to use all 100 pounds but i bought that much since they came in 50pound bags.

[CyberDrgn]

I used 75 lbs of gravel in my 90g and I wish I had gotten more, its 1/2 inch deep at the most.

[valerie]

yeah see that is what i thought and decided to get 2 bags. I want between 1 1/2"-2" of gravel.