DIY Stand - how perfectly flat must the stand be???

[BWoolf]

Hi all, I’m building a 2x4 and plywood stand for my 125 gallon aquarium. The aquarium is an Aqueon 125 that is 72” x 18” x 23” with the black plastic trim. My concern is how flat must the top of the stand be. I’m a machinist so I’m use to dealing with tolerances from a few tenth to a couple thousand of an inch. I’m thinking it might not to be with in those tolerances but I’m also not sure what it needs to be.

Any help on this would be greatly appreciated.

Also should I put any type of mat between the aquarium and the stand, I have read mixed ideas on this.

 

[Tamberav]

You don't use a mat with a tank with a black trim. Also I would say since it is a tank with a black trim, it actually doesn't need to be as perfect as a rimless. Mine is just on apiece of 4x8 sanded plywood. Just make sure the tank is level.

The trim protects the glass and helps with pressure points.

 

[BWoolf]

Cool thanks

 

[cooltowncorals]

I built one for a 125 with my brother first wood project I ever attempted I’m sure it wasn’t perfectly flat

We did use a board stop (wall; clamped on piece of wood) to make sure all the legs attached were the same length want to say like 4 per side and two in each corner then laid 2x4 on top and bottom

never had any problems with it boards were not plained or anything

you could plain top and bottom 2x4 if you wanted them super flat but I would imagine your floor would be as perfectly flat as your boards.

 

[jwilliams860]

With the trim on the tank the top piece of wood wont have to be super flat. As others said just make sure its level. In theory you wouldnt have to have the wood plate on top it would sit on the top plate that you make out of 2x4 if that makes sense. If you put a sheet of plywood on top that will give it some sheer strength. The weight of the tank will make everything settle some. If you make sure its level you wont have any issues.

 

[BWoolf]

Thanks, I appreciate your input. Everyone’s.

 

[Ratherbeflyen]

Rimmed tanks only have to be supported on the ends. In fact, if the center brace is taller than the ends, it will most likely break/crack the tank.

 

[mike550]

Rimmed tanks only have to be supported on the ends. In fact, if the center brace is taller than the ends, it will most likely break/crack the tank.

Wow. That’s amazing. Not sure if I’d do that in my house but that says a lot about tanks!

 

[PotatoPig]

Wow. That’s amazing. Not sure if I’d do that in my house but that says a lot about tanks!

Came to post the same picture. He’s one I took at the LFS with a 150 gallon rimmed tank (6 foot long).

Can’t really see it in the pic but there’s about 1/8” gap under the whole base. Even if there wasn’t the pieces under the long sides are little steel angles - the glass panel is around 100x stiffer than the angle so would carry 99%+ of the load anyway even if you had full contact to start with. Next time you’re at a fish store take a look at the stands - if they have stacked tanks you’ll see the same thing.

Even something like a 2x10 only has about 5-10% of the rigidity of the glass - so the glass would still do 90%+ of the work.

The tank functions as a U shaped beam. Only way the glass isn’t spanning is if you’ve preloaded the beams by curving them up, or jacking them and then installing supports. Or it’s on a thick slab of granite. Doing this is probably a bad idea - as Ratherbeflyen notes - you’re forcing loads into the tank it wasn’t designed for.

The #1 most important thing is to make sure the corners are fully supported and the load is going through them. If the tank is on a wood floor then the floor may deflect a tiny amount while filling up that could cause a gap at a corner. Probably less an issue if you have a wood frame with sheathing on it, but with many metal frames you might need to readjust the legs to make sure they’re all carrying the load.