Stand flatness

[kbennett]

Hello,
I finally got my 220 gallon tank the other day. It's in my garage just itching for me to figure out how to get it on my DIY stand.

The stand is a RocketEngineer design with plywood on the top. Since it is such a big tank, I am freaking out that it might not be perfectly flat. I've got a 5 foot level , but it teeters a 16th of an inch or so (or less) cutting across some plains. Most of the teetering is due to some loose laminations in the plywood that pushes down easily, but I don't want to take any chances. I am also worried that it might settle unevenly when the tank is full.

My tank has a plastic rim around the bottom with two cross bars underneath as well. I know I'm not supposed to put foam under it, but I was thinking about putting foam down and then putting another sheet of plywood on top so that there will be a little give. Will that work? Is it overkill?

Also, what kind of foam should I get?

Thanks for you help

[uncleof6]

Don't put foam under it. You know you are not supposed to, so why would you do so? You do not even need the plywood top... If the plywood is the problem, either buy some hardwood plywood that is not loose, or leave the plywood off altogether. If the tank still teeters, you need to do something with the stand rim.

[kbennett]

Foam cant go directly under the tank because it might push up on the glass. If I sandwich foam in between two sheets of plywood, isn't that better? Would it smooth everything out without the risk associated with foam under the plastic?

I guess my real question is: if I don't have a plywood top, how do I ensure my stand is level on all plains? I can't run the risk of putting the tank on and finding one corner low because I have to hire movers to lift it.

[woodnaquanut]

Do a google search for 'winding sticks'.

[uncleof6]

Foam cant go directly under the tank because it might push up on the glass. If I sandwich foam in between two sheets of plywood, isn't that better? Would it smooth everything out without the risk associated with foam under the plastic?

I guess my real question is: if I don't have a plywood top, how do I ensure my stand is level on all plains? I can't run the risk of putting the tank on and finding one corner low because I have to hire movers to lift it.


With a long straight edge, and a level the way it is supposed to be done. Can't build a stand the right way without those two items. A bench jointer comes in real handy also, to deal with the crook.

Without a top, if one corner is low, the stand is out of whack, and needs to be fixed. A plywood top will not fix that--sandwiching foam is a false sense of security. The tank needs solid co-planer support. There are no shortcuts, do it once, (or twice,) but do it right.

[kbennett]

I did it with a level an straight edge the first time. . . then I realized that my floor wasn't level :)

The plywood was never intended to make up for any issues in the design. I just put it there to raise the tank height and I thought I would be able to tell if it was perfectly flat by putting a straight edge down across it. It should sit flat at every angle. I had assumed that the plywood would lay flat, but I guess that was wishful thinking.

With your advice, I think what I will do is level the bottom (don't trust that the carpetted floor is level and it needs to be done anyway) and then check the top with a level/straight edge.

Can a 72" bubble level tell if you are out by 1/64th over 72"? How much can it be out?

Thanks again for your help

[uncleof6]

The larger issue with a carpeted floor is a tack strip tipping the tank out from the wall a 1/4" in.

I don't think that 1/64" is such a critical thing. Reasonably level would be the bubble in the center, with a 72" level. Yes you can discern 1/64" with a level, (if it is a good level) but I would say between the lines is close enough. However dead center is the goal.

Did you use a good quality hardwood ply for the top? I haven't had a problem with that, unless the ply got wet. If the ply is that wavy, I would look into another sheet (oak or cherry ply.)

[kbennett]

It is the best quality oak hardwood plywood Lowes had. . .
So probably just expensive crap.

I'm not worried about loose laminations because they press down easily - they were just making the straight edge teeter a bit.

I plan on leaving at least 4" between the stand and the wall so the tack strip shouldn't be an issue. Thanks for pointing it out though.

After scrutinizing it a bit more without the plywood, I think that it will work.
The proof will be when I put the tank on it.

Will the weight of the water even everything out a bit as well? I remember some calculations about flexing in wood in the giant stand building thread, but Its too big a thread to look through.

Thanks for your help!

[uncleof6]

Don't fill the tank till it sits flat and square on the stand without water. After that, the water is not going to matter much.


If you have a crook issue (the tank rocks end to end or back to front on the stand) that could be a problem. You don't want to use weight to fix this sort of thing.