Need help leveling 90g tank!! Gap under tank??

[Kallen]

The last few years has been rough with my hobby. Few years ago, I had a seal go bad. I have hardwood floors, and it was raining in my basement. So I removed the old seals and resealed the tank. Lasted 2 years, busted again. Gushed a lot worse. So I decided to get a new tank (this is about 5 months ago). After the new tank was up for about 2 months, I realized it was not sitting flush on the cabinet. I could take a piece of paper and freely slide it between the bottom of the tank and the cabinet. Only three corners were supporting the entire 90 gallon tank. So I drained off about half the water to reduce the stress on the glass until I could get a new cabinet.

Let me mention that my floor is not level, and the old cabinet had shims under one side. A level on top of the tank showed it was a little off, but not a LOT... I also realized that the floor of the cabinet (particle board) was severly warped. So I assumed the cabinet was at fault.

A few days ago I picked up a new cabinet. So tonight I started setting it up. The level on top had just the tiniest bit of the bubble outside the line, so I figured I was good to go, no shims. As I started to fill the tank, I kept an eye on the water level on both ends. I am a little under half full, and I realized I am way off from level again. Side-to-side is about 7/16 (.43) inch off. And front-to-back I am off a little over 1/8 inch. I took a piece of paper, and I can once again freely slide it between the tank and cabinet in the middle (side-to-side) but the sides and corners are firmly touching.

So, the new cabinet is definitely supporting the weight better than my original cabinet. But I am concerns about the almost half inch difference and the gap under the tank. So I need to know:

1) Is a gap big enough to allow paper to slide under normal or of concern???
2) Do i need to be concerned about the almost half inch or should I just go with it and not worry???

Thanks!

[Chris7495]

That would worry me as it could be putting all that pressure on one part of your tank, could be why your seal was going bad so frequently. My dad had a tank that he couldn't get level so he used a piece of wood under the tank when he figured out his floor was warped.

[Kallen]

Originally Posted by Chris7495

That would worry me as it could be putting all that pressure on one part of your tank, could be why your seal was going bad so frequently. My dad had a tank that he couldn't get level so he used a piece of wood under the tank when he figured out his floor was warped.

I've searched and found so many conflicting statements about being level. So say anything over 1/8 is a problem. Others say anything under an inch is ok...and everything in between. My concern is that shimming the old cabinet warped it, and I don't want the same fate to befall my new (and expensive) cabinet. Is .4" enough to stress the seals?

[Jesselav1233]

Could you maybe get some kind of 1/2 inch thick mat thats made out of some kind of material that conforms to things shapes like a memory foam or something put it under your whole tank so it might even out any pressure on the bottom of your tank. I'm not sure I'm just spit balling after reading your thread. These kind of problems drive my OCD tendencies crazy so I know how you feel.

[donker]

Being a little off perfectly level isn't really an issue, although !/2" over 4' is getting a bit out of my comfort zone. Having it on a surface that isn't perfectly flat does concern me, though. It's likely why the old tank sprang a leak. When I had a similar problem I used adhesive backed cork drawer liner. It seems to be just the right firmness to offer support but still deform before the tank does.

[Keithhjs]

My floor isn't level either and I shimmed under the stand with shims for a bathtub or water closet. A 1/2" out of plumb to me is well beyond acceptable levels especially if you have a glass tank.

[Wy Renegade]

First of all, the entire weight of the tank is supported on the ends, not anywhere in the middle, unless you have a tank over 6' long, and even then evidence would suggest it sits on the ends. If you need evidence of that, simply go look at how the prefad stands are all built; the only supports are on the two ends on the majority of pressboard stands. Being able to slide a piece of paper beneath the tank is not an issue, nor is it why your seals failed on the old tank. I've a 6' 100gallong tank that I can slide several pieces of paper underneath in the middle, and its been that way for over 20 years without issue. That said however, any type of twist or tweek in the cabinet or on the frame of the tank, like that caused by an unlevel stand (corner to corner) will cause the seals to pop. You want the top of the cabinet as level as possible. Shimes underneath the cabinet are not an issue, so long as it sits level, not twisted. In regards to placing something under the tank, be aware that in most cases placing something under the tank other than a company approved cabinet will void any warrenty you might have on the tank. This includes foam and/or custom stands.

[cinnamaldehyde]

I live in a very unlevel house, so I cut a blue foamie (one of the cheap camping ones you get at camping stores or even Walmart) to be about 1" bigger than the footprint of the tank, and put that under the tank. I find it levels the tank out nicely.

[Scottyhorse]

Is the bottom of your tank warped possibly?

[Kallen]

Update:

So I put 1/2" shims under one side, almost the entire length of the side. On the old stand I just had the corners shimmed. So this time around, I used long shims and the entire side is resting on it. I figured this would be better and might help. Filled with water and its dead level. (Tank is leveler than it has ever been).
The only concern this created was the setup now easily rocks front-to-back because of being shimmed so high. So I took a couple scrap pieces of thin wood and slid under the middle of the cabinet (in the front and the back both) and this seems to have stabilized it greatly. I can still rock it a little but not enough to worry me of tipping. Also, once the 720 lbs of water was added and the shims added, the middle of the tank now touched the middle of the cabinet. I am still concerned about being shimmed so high...