What kind of Foam to use

[Sky042]

I'm going to be using some large rocks as decoration in my 125. I've heard it's a good idea to lay foam down under the sand to distribute the weight and protect the glass. Anyone know what kind of foam to use?

 

[Dubby]

I've heard of polystyrene being used under the tank to distribute the weight. Are we talking the same thing here???

 

[Bloo]

Nope - I think he mean "inside" the tank.

 

[ncjharris]

extruded/blown polystyrene should work - ensure its not impregnated or dyed with anything that could leach into the water.

In addition check the density and pourosity of it to make sure it can distribute the weight well.

One thing to watch out for - make sure it is fixed flat to the bottom of the tank - if there are any pockets let underneath that could be a recipie for disaster, if anything gets trapped in their it will create pockets of nasty gas.

 

[abstract]

IMO you dont want to use polystyrene inside the tank...after it gets water in the pores, the cushion just really isn't there anymore...you should use polystyrene UNDER the tank and then eggcrate inside the tank to distribute the weight evenly....you can find eggcrate in the suspended ceiling section of any home improvement store (the people in the UK have a little more difficulty from what i've heard and sometimes have to order online)..

eggcrate looks like this
it's sold in 2'x4' sheets used over lighting fixtures...can be cut with a hacksaw or even strong scissors

 

[Sky042]

IMO you dont want to use polystyrene inside the tank...after it gets water in the pores, the cushion just really isn't there anymore...you should use polystyrene UNDER the tank and then eggcrate inside the tank to distribute the weight evenly....you can find eggcrate in the suspended ceiling section of any home improvement store (the people in the UK have a little more difficulty from what i've heard and sometimes have to order online)..

eggcrate looks like this
it's sold in 2'x4' sheets used over lighting fixtures...can be cut with a hacksaw or even strong scissors

I actually have eggcrate I use it in my wet/dry filter.
But I wouldn't think that would do much to help make sure the rocks don't crack the bottom of the tank.

 

[funkybodal]

I think that eggcrate would be a good idea as it would allow for good circulation under the rocks, especially if they're large, thus avoiding the creation of 'dead-spots' where there is little water flow.

 

[Sky042]

I think that eggcrate would be a good idea as it would allow for good circulation under the rocks, especially if they're large, thus avoiding the creation of 'dead-spots' where there is little water flow.

There won't be any water flow. There will be a sand bottom under the rocks and everything.

 

[Tolak]

The idea behind the eggcrate is to spread the weight of the larger rocks, so you don't have a lot of pressure in a very small area. A pointy corner of a rock can crack the bottom, eggcrate spreads this pencil point sharp area over a few square inches. Even with sand or gravel under larger rocks, over time the heavier rock can settle downward. Better to be safe than sorry.

Tolak

 

[abstract]

the point of eggcrate (and anything you put under rock structures in your tank) is to distribute the weight evenly....not to CUSHION anything....there are hundreds of cichlids (and reef tanks) owners that swear by it with their rock (and live rock) structures weighing in at tens (and sometimes hundreds) of pounds ....i don't know about you but i would take the advice of the experts out there who all use it and suggest it to other fishkeepers....

you put polystyrene under your tank just in case a small pebble or something similar is resting underneath it which would crack the glass....you put eggcrate underneath rock structures to distribute the weight evenly across the entire bottom of the tank....if, for example you decide to do half of the tank as a big rock structure, the other half as open swimming area - you would still use a piece of eggcrate cut to the size of the entire bottom of the tank, not half....that way the weight is dispersed...don't take my word for it though

http/www.cichlidforums.com/printthread.p...=&threadid=2659

http/www.skepticalaquarist.com/docs/aqua...ing/rocks.shtml (see "Caves" section)

i could post hundreds of links

 

[SarahBravo]

Egg crate just spreads the weight of the rocks out - instead of a lot of weight in a few places where the rock touches the glass, the weight is spread out all over the eggcrate to all over the glass. Also stops scratches on the glass. I know Steve (Baldranger) got some eggcrate in the UK - maybe PM him or search for threads on here.

 

[shuhu]

if you already had an UGF you can simply use the bottom of it instead of having to cut the Egg crate to fit your tank bottom, that is if it's difficult for you to find Egg crate in your area

 

[Sky042]

if you already had an UGF you can simply use the bottom of it instead of having to cut the Egg crate to fit your tank bottom, that is if it's difficult for you to find Egg crate in your area

No egg crate is easy though not cheap to purchase here.
I just thought it was some form of foam and not eg crate that was being used.
Guess home depot is on my long list of places to stop

 

[abstract]

if you already had an UGF you can simply use the bottom of it instead of having to cut the Egg crate to fit your tank bottom, that is if it's difficult for you to find Egg crate in your area

No egg crate is easy though not cheap to purchase here.
I just thought it was some form of foam and not eg crate that was being used.
Guess home depot is on my long list of places to stop

if you're not already, you should still probably use the polystyrene foam underneath the tank, especially on a tank so large!

 

[Cheese Specialist]

Maybe ask CFC, I think he uses big rocks in his aquaria. Or freshmike if he is still around.