Stand question - it level but

[imfsub12]

Hi we just got our stand made and one simple question. Oh its 7 feet long x 24 wide (250 g)

We placed out plywood on top and like any wood it has some dips not much like 0 to 1/16th... in some spots.

But its level.. I'm going to be placing under the tank a workout mat for the imperfections as per my LFS request for the build for the tank.

This should do the trick?

Or I'm being to worried as our contractor is a perfectionist as he builds high end kitchen and he need it to be perfect flat.

Here is a picture of one part as you will see its about the 0 to 1/16th the it goes flat for a bit then off again.

Note please be nice about my contractor he does good work we are looking for advice. https://uploads.tapatalk-cdn.com/20170401/b4e973b89d3a3d05ac64847b15e2e85f.jpghttps://uploads.tapatalk-cdn.com/20170401/e506f9f52bb885660fae3c224b6e1852.jpg

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[Sacohen]

When the tank is on and water is added it should flatten everything out.
I have used sheets of foam insulation in the past on my 125 gallon (6' long 2' wide) tank.
My 4' 90 and 55 gallon tanks used nothing and they were fine.


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[imfsub12]

When the tank is on and water is added it should flatten everything out.
I have used sheets of foam insulation in the past on my 125 gallon (6' long 2' wide) tank.
My 4' 90 and 55 gallon tanks used nothing and they were fine.


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Thanks.

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[Lsufan]

I think u will get different opinions but imo I would want it to be flat. U don't say if it's a rimmed or rimless tank but a rimmed tank needs to be supported around the whole perimeter. With the stand not in plane it will only be touching where it is flat, so it won't be fully supported. That will stress the tank.

I don't think I would rely on the tank to flatten the stand out. For all we know the gap may go away but it could be the tank stressing & not the stand flattening out. It's hard to build a stand when it is framed out of dimensional lumber without a planer. U won't find boards that are perfectly straight, they all have a little crown in them. I usually make sure that the framing is all in plane before I put the plywood on top.

If u decide to do something about it I would think about using a floor leveling compound on top of the plywood to get it all in plane & perfectly flat. I would think about doing something like that before putting a pad underneath it if it is a rimmed tank.

[salty joe]

It is tough to make something perfectly flat using dimensional lumber.

I had the same problem, so I taped wax paper to the rim of my 75 G and put a layer of Bondo on the perimeter of the top of the stand. Then I set the tank in the Bondo. I marked the back of the tank in case the tank was not perfectly true.

After 5 or 6 years the tank came down and the Bondo was still like new. It never got flooded, but it did get wet a few times.

[luvreefs23]

I'd note high spots and do some sanding. On a side note when I have researched support for tanks that are rimmed its recommended that all 4 corners be supported, but I'd still want as much as possible supports all the way around.

[imfsub12]

It's a custom built flat bottom tank
I think we will be ok
I'm placing 2 rubber mats under it like foam.




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[CrayolaViolence]

I have this same issue and have gotten no real responses. It's a rimmed tank and the top of the stand dips slightly at opposing corners producing about 1mm of clearance.

[fishgate]

I have this same issue and have gotten no real responses. It's a rimmed tank and the top of the stand dips slightly at opposing corners producing about 1mm of clearance.

I put a shim under the plywood before I screwed it to the stand front and back and the gap went away.

[CrayolaViolence]

When the tank is on and water is added it should flatten everything out.
I have used sheets of foam insulation in the past on my 125 gallon (6' long 2' wide) tank.
My 4' 90 and 55 gallon tanks used nothing and they were fine.


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I've heard to not use foam with a rimmed tank. Were yours rimmed?

[Sacohen]

All of my tsnks have been rimmed.
I too have heard that, but it was after i had the 125.
The 55 had oneof those flimsy store bought plywood cabinets.
The 90 has a home made stand made out of 2 x 4's.

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[abrooks12376]

If it's a rimless, flat bottom tank you'll want a compression medium under there for sure. When the water weight settles it onto the stand a nail head could blow that thing apart. Yoga mats are a good choice, or a high density foam camping pad, cut to fit.

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[Lsufan]

I've heard to not use foam with a rimmed tank. Were yours rimmed?

U are right, your not supposed to put foam under a rimmed tank. I think one of the reasons U aren't supposed to use it is because it will compress where the rim is & end up putting pressure on the bottom pane of glass if it compresses enough around the rim to where it touches the bottom pane. The bottom pane of glass isn't supposed to touch anything except the trim. Most rimmed tanks are made with the 4 sides sitting on top of the bottom. Rimmed tanks are supposed to be supported along all 4 edges, basically along the whole bottom trim. They don't even really need a plywood top. A rimless the whole bottom has to be supported.
A rimless tank I would check with the manufacturer to see what size & what type of foam they recommend. Especially on a new tank so u don't void any type of warranty by using the wrong foam.

Something like fishgate mentioned should work also if it's just a small amount like the op. U can shim under the plywood before screwing it down & use liquid nail inbetween the frame & plywood. The liquid nail gets hard & it would fill in the small voids between the frame & plywood.

To the op, I assumed the carpenter glued the plywood down but it may be worth asking him because if he didn't then it would be a relatively easy fix.

[uncleof6]

Using the weight of the tank to "flatten" the stand, is asking... no... ... begging for the tank to explode. Newton's laws... all the pressure down, is also the same pressure up into the tank....

[davocean]

I personally would not rely on foam to absorb deviations.
As for foam use on trimmed tanks many have done it, wrong or right, the greater risk seems to be reverse pressure on bottom if foam is too thick supposedly.
Really everyone should check w/ tank manufacturer and do exactly as they advise, every manufacturer may have a different recommendation and not following guidelines can void warranty.

[uncleof6]

I personally would not rely on foam to absorb deviations.
As for foam use on trimmed tanks many have done it, wrong or right, the greater risk seems to be reverse pressure on bottom if foam is too thick supposedly.
Really everyone should check w/ tank manufacturer and do exactly as they advise, every manufacturer may have a different recommendation and not following guidelines can void warranty.

Quite agree. Only the manufacturer knows for sure. However, rimless tanks most always need "something" under them to prevent point loading which will indeed shatter the bottom panel. I don't know a responsible builder that does not recommend "something" to prevent point loading under the bottom of a rimless tank; nor do I know of a manufacturer that OK with: "put foam under a rimmed tank." If nothing at all, foam under a rimmed tank is just plain useless.

[CrayolaViolence]

Would a piece of foam with a board on top work? The reason I ask this is because even if I take off the top and shim it, I won't know if it's flat until the tank is back up there. Once everything is dried (if I use glue) then I could still have the same issue as before.

I was hoping putting down a piece of styrofoam with a flat high grade wood top, would absorb any of the unevenness in the original top. Right now I am at a loss as to what to do to fix this. We entertained the idea of putty but getting the putty onto the stand and covered with wax paper before it dries and getting the tank in place without smearing it everywhere, just doesn't seem plausible.
Another thought about using foam under the rimmed tank was to cut out the center of the foam, leaving only an outline for the rim to sit on. Has anyone ever done this?

I'm still leaning toward the foam board plus wood on top. Has anyone had any success doing this method?

Thanks so much.

[Stefanm]

Just put the Styrofoam, it'll take out the minor imperfections of the ply once filled, even my stand had a similar issue and I'm sure there are many thousands of aquariums built the same way, running without issue. Unless the dips are of a large diameter I would worry, you could always sand and fill the imperfections.

[salty joe]

We entertained the idea of putty but getting the putty onto the stand and covered with wax paper before it dries and getting the tank in place without smearing it everywhere, just doesn't seem plausible.

Thanks so much.

Tape the wax paper to the tank. Use masking tape on your stand to make cleanup a breeze. I like the Bondo because it's about as close to perfect as you'll get in this world.
Like fishgate said, shimming the plywood is another way. Sanding was mentioned as another way to skin that cat.

I guess the question is, how much deviance is acceptable for a given rimmed tank? IMO, 1/16" is pushing your luck but IDK. A friend had a 90 rimmed fail at a seam after a year or so due to an uneven stand.

For the OP with a rimless tank and stand with a 1/16" deviance - a dense foam pad sounds OK to me, it wouldn't hurt to flatten it a bit-as mentioned contact the manufacturer.