rock size/weight question?

[id10t]

Finally got a bigger tank (36lx20hx12w) and I'm thinking of going with sand and rocks only, no plants and minimal lighting...

I've got this one nice rock in my yard with some great natural holes & such in it, and I'd like to use it (its limerock/chirt, same stuff my well water has been in the past long while...). It physically fits (12lx14hx6w), but it weighs 32 pounds according to my bathroom scale.

Is this too much weight in one spot? The "foot" of it would be the 12x6 side, so if my reckonin is correct, thats about one half pound per square inch, in addition to the layer of sand on the bottom of the tank.... safe?


(sorry for the cross post)

 

[Bderick67]

personally I would place in the tank after the sand had been added. To make sure it is safe you could cut a piece of egg crate and put it on the bottom of the tank first.

 

[captainawesome]

Ah, egg crate, the answer to al tank ornament questions. If you have an ugf it shouldn't be as bad. At least I have never had problems.

 

[id10t]

Got some eggcrate today....

Sand is already in the tank (along with 2 small rocks and some danios), so I guess I'll "press" the eggcrate down into existing sand, add a little more sand on top, and then the Big Rock.

 

[ammerman19]

yeah egg crate or on top of the substrate will do fine. You already have the right idea by figuring the lbs/sq. in. The problem with large rocks though is that they are not a flat surface which is why they should be placed on eggcrate or substrate to distribute the force over a larger area. A rock will normally only sit on a couple of points which add up to a very small area that load is distributed under. So if this rock were to be on the bottom or in a bare tank you would probably be looking at a much higher force/area.

 

[merc123]

I would take the sand out, put in the eggcrate, add enough sand to fill in the eggcrate, put the rock in so it supports itself freestanding, then re-add the sand.

If you ever get anything that likes to dig or burrow it could be possible it will dig under the rock and collapse it on itself. That is why you put the rock then the sand.

 

[id10t]

Eggcrate is in, but the Big Rock is not...

The more I got ready to put it in, the heavier and heavier it seemed. Bathroom scale didn't change... but I thought it may be better to be safe than sorry, so I have the nice looking Big Rock outside, and 3 smaller rocks (tested, scrubbed, boiled and artistically arranged) in there instead.

May end up pulling it out and doing a slate DIY thing instead though....

 

[steveprovot]

http://youtube.com/watch?v=PgEwEiTyYcs
check this out it will ease ur mind a bunch. i had 150 lbs of rock in my 150 that was 1/2 inch glass but it was alot of rocks plus well over 100 pounds of gravel
i would put it in as long as you dont drop it you will be fine, with the egg crate to you would be golden

 

[gomezladdams]

You got the eggcrate in youre good to go.Lots of people have heavier rocks in thier tanks.
And free holey rocks in your back yard!?!,youre if you dont use them.
Sounds like you got optimum conditions for tang cichlid setups

 

[Nova 8]

Look at the size of the rock in my aquarium and I don't even worry, glass is strong esp. when well supported. I'd get the rock out and weight it for you but I cant pick it up by myself, it was a struggle getting it in there with a mate.