Foam underlayment?

[rybitski]

I have a 90 G glass aquarium that I am building a stand for and I am wondering what is the best underlayment for it. I have seen a lot of the acrylic aquariums placed on some dense blue insulation foam. I have also seen some placed on plywood and then some placed on a frame that is the same size as the tank. The stand I am building has a 2x4 frame that is the same footprint as the tank. Would there be any benefit to placing plywood on top of that or both ply and foam? I am just concerned about my tank cracking from stress and would appreciate any input or insight.

Here is a picture of the stand I am working on, please ignore the mess in the background. There will be a 90 G that sits on the right and a 20 G Tall that sits even with the top of the 90 on the right.

 

[Troylee]

Plywood would help stabilize the stand foam is not needed.... For sure don't want to put foam under a glass tank unless a manufacturer recommends it..... Glass tanks sit on the plastic trim and the bottom pane of glass is receessed if you set it on foam your putting pressure on the bottom glass and not on the uprights "not a wise idea" I wouldn't even put it under acrylic tanks personally..... I still haven't figured out why people do use it???:tongue:

 

[UncleJT]

I still haven't figured out why people do use it???:tongue:

Several rimless glass manufacturers recommend it including Reef-Savvy, the big tank builder everyone in Florida use and recommend.

Edit:

ADA also sells what they call a "Garden Mat" to go underneath their rimless glass tanks. It's a closed-cell foam, probably evazote, which I have used under my ADA tanks in the past. I will be using 3/8" evazote under my new 24" rimless cube.

But Troy is correct, on a tank with a frame, you really don't want foam.

 

[dougers31]

I have used 3/8 in styro to help even out any imperfections in my homemade stand. I would think using 1/4in under the frame would be too thin to ever make contact with the glass but that's just my opinion.

 

[SeeingGreen]

I thought the concept was for a bit of insulation, glass conducts quote well, any little increase helps right? Then again I am in the land of ice in Wisconsin.

 

[Troylee]

I agree with this.... Reason I said if the manufacturer recommends it.... Some glass builders do build there tanks where the sides sit on the bottom like acrylic... I used it one time only and that was on drop off tank because the stand was a split level... Well after a year the foam settled and the tank was out of wack causing unnessacary stress on the seams and was leading to premature failure.... Arrrr I would avoid it at all costs if possible personally....

Several rimless glass manufacturers recommend it including Reef-Savvy, the big tank builder everyone in Florida use and recommend.

Edit:

ADA also sells what they call a "Garden Mat" to go underneath their rimless glass tanks. It's a closed-cell foam, probably evazote, which I have used under my ADA tanks in the past. I will be using 3/8" evazote under my new 24" rimless cube.

But Troy is correct, on a tank with a frame, you really don't want foam.

 

[rybitski]

Thanks for all of the input! So it seems that you guys have helped me decide to stay away from foam, but what about plywood vs 2x4 frame? Any personal experiences anyone cares to share?
Troylee: since we are on the topic of your drop off tank I want to let you know how impressed I was by it. Wonderful job and really awesome design.

 

[UncleJT]

Thanks for all of the input! So it seems that you guys have helped me decide to stay away from foam, but what about plywood vs 2x4 frame?

The key here is a perfectly flat surface for the frame to rest on. If the tank frame rests perfectly on th 2x4's (i.e. you can't stick a sheet of paper anywhere under the frame when sitting on the stand), you are good to go. If you have any gaps, a piece of thick (3/4" plywood) may help.

 

[Troylee]

Thanks for all of the input! So it seems that you guys have helped me decide to stay away from foam, but what about plywood vs 2x4 frame? Any personal experiences anyone cares to share?
Troylee: since we are on the topic of your drop off tank I want to let you know how impressed I was by it. Wonderful job and really awesome design.

thank you for the kind words......

The key here is a perfectly flat surface for the frame to rest on. If the tank frame rests perfectly on th 2x4's (i.e. you can't stick a sheet of paper anywhere under the frame when sitting on the stand), you are good to go. If you have any gaps, a piece of thick (3/4" plywood) may help.

agreed .... nice solid info right there..

 

[dougers31]

Hopefully this adds to the discussion... Should the plywood be screwed down or free floating? I would think if it was screwed down it might warp or not be level...

 

[Troylee]

Hopefully this adds to the discussion... Should the plywood be screwed down or free floating? I would think if it was screwed down it might warp or not be level...

i have always screwed it down myself to help strengthen the stand.....you can back a screw off here or there and shim under the plywood accordingly to keep it perfectly flat.....thats a bonus of using a plywood top you can shim accordingly.... especially since 2x4's don't really come flat unless you plain them or find some good lumber and pay a higher dollar amount most of the stuff you find at the big box stores is still wet and twists and warps.....also never shim under the tank you always want to shim under the stand on the floor......

 

[UncleJT]

Hopefully this adds to the discussion... Should the plywood be screwed down or free floating? I would think if it was screwed down it might warp or not be level...

Oh my new stand, I had to actually screw mine down to improve the flatness of the surface. Even expensive 3/4" and 1" hardwood plywood can be slightly warped. Additionally, screwing or somehow other tacking the plywood down in place makes it much easier to set the tank on the stand. Don't know how many times in the past I've cursed out a floating surface for moving while I was getting the tank in place.

 

[rybitski]

i have always screwed it down myself to help strengthen the stand.....you can back a screw off here or there and shim under the plywood accordingly to keep it perfectly flat.....thats a bonus of using a plywood top you can shim accordingly...

That is what I was thinking, but wanted to make sure that it wasn't bad for the aquarium. I would be very disappointed if my diy stand ruined my tank. Thanks again for the great input!

 

[NaplesAquatics]

FWIW, I've used foam under every tank for several decades now. No problems, haven't had a leak since I started doing this. Acrylic, glass, plywood, etc.

Jeff

 

[BHHOWARD]

Anyone using shower pan liner (pvc) or similar materials under tanks?

 

[Reef Breeders]

There is no need for foam, it will have no benefits, and looks terrible. Just use a plywood top and a level

 

[rkrolak1]

Foam definitely not needed. Foam is usually installed under acrylic tanks because there is no frame support keeping tank from bulging at bottom.
Your frame is quite sufficient for your 90 but plywood would give it extra support although not needed,plus it add sextra weight to stand. You might think about putting a center support on the back between top and bottom 2x4 frame.Excellent design!

 

[rybitski]

Excellent design!

Thanks :smile:

 

[rybitski]

Here is a picture of the stand thus far.. I actually have it fully covered except for the doors, but of course forgot to snap a picture. I am actually working on this in the university scene shop and am competing with the summer govenor school for shop time. So I have only been able to work on this for a total of about 5 hours since the last picture.. I get the shop again Wednesday and will hopefully get this finished up and ready for paint.