How level is level?

[kkutac001]

Heya. I did a freshwater test of my tank and stand last night. The tank is glass, 60x18x20. I had to shim the bottom since it's on a tile floor. Before filling with ro/di water, I used bubble levels (one four foot long, one 8 inches long) to ensure it was level both lengthwise as well as front-to-back.

It is mostly filled now, about an inch below where the final waterline will be. Problem is: it appears that a 1/8" unlevel-ness developed during the filling of the tank, in the lengthwise direction. That is about 3mm.

Is 1/8" over a 60" length unacceptable? Or is it: might work, but is not worth risking? Or is it: I'm being overly paranoid?

Thanks for any advice/experience you care to give. ..Karl

[Instar]

If you have an overflow and sump, it's not acceptable unless it tilts toward the end of the overflow. Once running, it will make you crazy unless its level, especially since you tried to get it level to such a degree. Incidently I may be biased as I have a 1,000 gallon/hr return on one thats not level and a ball valve to cut it back to just a couple hundred gallons for just the same amount of unlevel as you have now because the waves go over the side of the tank rather than go over the dam. I wish I had noticed it earlier and fixed it. I thought it wouldn't be a problem but that turned out to be a bad decision. Also, if that stand is not square and level cross ways (X) as well, fix it so it doesn't torque the tank once its full of water so you don't have to worry about it. If it's basically a squared up stand and your overflow is low enough, you may not have the same experience as mine with waves over the lip of the tank. You just have to evaluate that at your end. A 3mm tilt won't break the tank so long as its an even square stand support on all sides but level is always better. 3mm will affect the overflow to the sump if there is one.

[kkutac001]

I am trying to include an ascii-esque diagram with measurements, but the font is being translated weirdly. Still, here it is. The numbers are where I used a dowl to take a 'pole' reading of the height of the water at eight different points within the tank. I took a 'reading' of the water height at eight points, starting near the back-right corner, proceeding in an order shown here:
back of tank
------------------------------
| 7 5 3 1 |
| |
| 8 6 4 2 |
------------------------------
front

1 - 15 14/16 (i.e. 15 7/8)
2 - 15 14/16
3 - 15 14/16
4 - 15 14/16
5 - 15 13/16
6 - 15 13/16
7 - 15 12/16 (i.e. 15 3/4)
8 - 15 12/16

So, it seems to me that front-to-back is level, it is only on the left side that it is 1/8" low. If I understand this, it means the shimming on the left side needs to be raised. I don't think the tank is being torqued; just squarely tilted, if that makes any sense.
I do have a 3 foot Calfo installed across the back of the tank, so the levelling issue you refer to re: the overflow is probably going to be a factor if left as-is.
Based on this comment of yours:

A 3mm tilt won't break the tank so long as its an even square stand support on all sides but level is always better. 3mm will affect the overflow to the sump if there is one.

sounds like it'll be better in the long run to drain, shim up the left side 1/8", then refill.
Thanks, Karl

[Bill S]

My 55 is about 1/2" off from one end to the other. Drives me nuts, but it's been up for years. Look at some in the LFSs and you will see they are WAY out of level. That being said, it's a LOT easier to do now rather than later.

[kkutac001]

Thanks, Bill. I think I'd be in the same boat: I think it'd drive me nuts (or maybe, nuttier is a better choice of words). I will re-level while it is still merely inconvenient, instead of harrowing. ..Karl

[Shark_Bait]

You will probably have to shim more than 1/8" My tank is off that same amount and thought I could shim and fill. Well you can but fill then check again. The shim compresses under the water weight. SO where I was level I am again lopsided after time. Good luck

[matt]

Yep, that's why they make metal shims. Ideally, if your floor is not level, you should make a platform for the tank, level the platform exactly, then try the tank. Guess what? Many aquarium stands are off level all by themselves, so it's back to shimming. What I did on my old 110 was make a plywood platform with 2x4 braces underneath, and put shims between the braces and plywood as needed. (I have an old house that's nowhere near level) Putting the shims in that way meant there was still complete contact between the tank/platform, and platform/floor. It's a PITA, but better to deal with it now than a few months down the road. Funny thing, my corner tank went right on the floor not more than 6 feet from where the 110 used to be, and it's really close to level.

[kkutac001]

How's this for non-thinking, dumb moves: in an earlier reply, I mentioned 'shimming up the left side', i.e. the side with a LOWER water height. Doh! Wrong side. I should have been lowering that side! Grrh. Still, I have emptied all but about 2 inches of water. I'm definitely wanting to get this levelled out now, as opposed to six months from now. So, I'll empty the rest of the water and basically start over.
Those wooden shims definitely compress. I have some of that brown peg board -- the kind with no holes, though. It comes in a couple of thicknesses. It doesn't seem compressible. I wonder if it'd work. Matt -- where does one buy metal shims? Thanks, and to everyone who replied so far. ..Karl

[matt]

I guess you could get them at HD, I'm not really sure. But if you have a wooden stand and all the weight is on a small metal shim, the stand could compress around the shim, plus it puts alot of weight on individual tiles. It's really best to find some way of spreading out the weight by having as much contact between stand and floor as you can.

[hoho19]

would a 3/4 inch piece of rigid foam work? I'm planning on doing that when I build my stand to sit on my tile floor.