Foam under a SeaStar tank?

[Aquattro]

Originally Posted by MitchM

Oh, no!

so far my story is that it's a leaking bulkhead, accumulating water in the bottom trim. It's dripping back into the sump, so that's a good thing. Right?

[Reefer Rob]

The foam on all tanks should only be max 4" wide around the perimeter of the tank, allowing the center of the bottom glass to float.

[The Grizz]

So what if you have a tank that has the trim and you have holes drilled down the center of the tank for returns?

Not sure if the tank has a floating bottom yet but with all the rock that is going to go in it and sand how do you support the glass so it does not break from where the holes are?

[Borderjumper]

Originally Posted by Aquattro

so far my story is that it's a leaking bulkhead, accumulating water in the bottom trim. It's dripping back into the sump, so that's a good thing. Right?

I read your first post and just went OMG! It's contagious ! I'm glad it's "just" a bulkhead. Sounds like if it's leaking into the sump you haven't lost any water, so that's a good thing.

[Borderjumper]

I've googled all morning, and what I am finding is.. Never put foam under a rimmed tank. A rimmed tank is designed so that the weight of the tank sits on the rim, which displaces the weight up the sides vertically. makes sense, as glass it strong vertically and weak horizontally. IF you put a rimmed tank on styrofoam, the weight bearing edge will compress into the foam until the glass is being pushed down onto the foam, your now messing with the design intent and instead of all the force of the weight being transferred vertically up the sides, it's also pressing up on the glass bottom which eventually cause it to flex, and as I know only too well, horizontal glass doesn't flex well when the corners are being pinned down by over a 1000lbs of water and rock.

[MitchM]

Originally Posted by Aquattro

so far my story is that it's a leaking bulkhead, accumulating water in the bottom trim. It's dripping back into the sump, so that's a good thing. Right?

Um no, Brad, any leak is a bad thing - otherwise Borderjumper would be overjoyed right now...

I don't get how the styrofoam under the tank would be a bad thing. If the glass is supported, then it's supported and should be stronger.
I can see if the supporting structure is uneven or warped, then you would have a problem.

Mitch

[Borderjumper]

Originally Posted by MitchM

Um no, Brad, any leak is a bad thing - otherwise Borderjumper would be overjoyed right now...

I don't get how the styrofoam under the tank would be a bad thing. If the glass is supported, then it's supported and should be stronger.
I can see if the supporting structure is uneven or warped, then you would have a problem.

Mitch

I think it's a very fine line between the bottom glass being supported, and the bottom glass being pushed up by the foam as the edges compress down.

[MitchM]

It shouldn't be that fine of a line. I've had 6' pieces of glass bow out 1/4" with no ill effects. Pink foam doesn't compress that much, does it?
A couple thousand pounds of water and rock pressure on the bottom glass should balance out the downward pressure from the edges. That would result in less pressure on the edges.
(just trying to wrap my head around the physics of the foam problem)

Mitch

[Borderjumper]

Originally Posted by MitchM

It shouldn't be that fine of a line. I've had 6' pieces of glass bow out 1/4" with no ill effects. Pink foam doesn't compress that much, does it?
A couple thousand pounds of water and rock pressure on the bottom glass should balance out the downward pressure from the edges. That would result in less pressure on the edges.
(just trying to wrap my head around the physics of the foam problem)

Mitch

If you look at the picture I posted above, the foam WAS compressed visibly along the edges. My theory is it compressed as much as it could until it made the bottom so tight it popped.

We just popped a piece of the trim off, and this tank is bottom glass with the sides all on top of the bottom glass.