New tank not sitting totally flush on stand surface. How should I handle this?

[hb1547]

I'm setting up a 55 gallon long tank on a DIY stand. The DIY stand has a 3/4" maple plywood top. The tank is a plastic rimmed Aqueon tank.

I found that the tank is leaning on its back rim and most of the front rim is not touching the stand. There's a small gap of about 2mm between the tank and the stand surface -- enough that I can slide an index card under a good portion of the tank rim. I can very slightly rock the tank front to back on the stand.

My interpretation is that even if I level the tank, it's the tank still can't sit totally flush on the stand.

Not sure what the best path forward is. My guess is the surface of the stand is very slightly warped, but I feel it's beyond my basic DIY skills to find and fix such a small variation.

I could put some kind of foam under the tank, but since it's a rimmed tank I understand that's not the best approach since it would put pressure on the glass bottom.

One thing I've read is that plywood tops can flatten out a bit once they become accustomed to the weight. My current best plan is to load up the tank with the substrate and heavy hardscape that I planned to use, then see whether the issue resolves itself. However I think it'll be tough to tell whether the issue resolved because the plywood top became flatter or because the tank twisted...

Any other ideas?

 

[Andy Sager]

Are the 4 corners of the tank sitting flush on the stand?

 

[hb1547]

No, not initially. Basically 3 corners are sitting flush at any given time, and I can rock it back and forth to change which corner is slightly elevated (back right VS front left).

I did add 50lbs of sand and a little water (enough to start leveling) and it definitely did reduce the gap. I can add another 50lbs later today once I finish prepping it.

 

[Aiken Drum]

Just be careful. Loading the aquarium will put stress on the glass the same as filling it with water would, twist it, and could cause failure. Id replace the stand.

 

[hb1547]

Thanks. My current plan is to load in the sand and hardscape initially, which will probably be ~150 lbs total or so (I figure sand would be easier to clean if the tank burst than water). I'll check regularly to see whether the tank is twisting or leveling out.

Replacing the stand is an option but it's an expensive one. Would an alternative to be to add a second layer of plywood between the current top of the stand and the tank? Again, the current stand top is already a 3/4" plywood top.

 

[Airborne 82nd]

I would cut another plywood top before leaving it like it is.

 

[Andy Sager]

Thanks. My current plan is to load in the sand and hardscape initially, which will probably be ~150 lbs total or so (I figure sand would be easier to clean if the tank burst than water). I'll check regularly to see whether the tank is twisting or leveling out.

Replacing the stand is an option but it's an expensive one. Would an alternative to be to add a second layer of plywood between the current top of the stand and the tank? Again, the current stand top is already a 3/4" plywood top.

I would check if the floor is level first. If it isn't, you can try shimming it and that should help. If it is, I'll say this: I use styrofoam under every tank I set up. From 10 gallons on up. I don't care if they have the plastic trim or not. I have 40 year old tanks with trims that still hold water. I use this styro: 3/4 in. x 1.25 ft. x 4 ft. R-2.65 Polystyrene Panel Insulation Sheathing (6-Pack) 150705 - The Home Depot. It's thick enough to make up for any small gaps so that the base sits level. This is a pic of my 40 gallon long ( same dimensions of a 55 only not as tall) which I have had since the 1980s. It's been moved at least 5 times since then. Notice it's sitting on double pieces of styro " just in case" the single thickness wasn't enough because the floor is purposely slanted to drain water from the floor in my hatchery. The second pic is of a 30 gallon long that I've had as long as the 40. It's the tank under the 40. You don't have to styro the whole base, just the edges.
The choice of course is yours.

 

[hb1547]

I added in the sand. The wobble is reduced and the tank does seem closer to flush with the surface. I no longer see light gaps at the corners, though I'm still able to pass a piece of paper under one of them (but just an inch or two away I cannot).

I spent some time leveling the stand and got it pretty close, or at least closer than it was before. Here are the current relative heights of each corner. I'll check again tomorrow and see whether it's changed. Thanks for the recommendation on the foam, I may take that route on the edges if needed.

 

[Karen LeQ]

The first thing I would do is to check the tank itself to ensure the rim is not warped as in a manufacturer defect.

Then I would check the surface of the stand to determine its overall flatness.

Use a bubble level to determine where the gaps are and whether or not a good wood filler (suggest floor levelling compound) can be used to flatten out the surface. If that is not an option then I would install a new piece of plywood over the existing. Ensure its going to be level before completely fastening down.

Cheers

 

[Airborne 82nd]

You have a lot of good things to try. You have to check 3 things tank bottom stand top and your floor. When you loaded up your tank what did you flex? If it was the tank that is bad news. The best way to check the tank is with a sheet of glass it is the flattest thing you will find turn the tank upside down and put a sheet of glass on it to see if it sits flat on all corners. If it does it is one of the other two.