Unlevel Tank

[stimpy4242]

Well after the move, it has become clear that the new house is not as level as the old house...
In fact from front left corner to back right corner there is a height difference of about 1". Now I have read plenty of posts on here about unlevel tanks and how everyone says this creates a ton of stress. I am curious if this stress is any worse than if the tank was just full of water and nothing else. Also most of those posts have somoething say, well its bad, but mine has been unlevel and I have had no problems.
The tank is completely setup at this point and I am definitely not breaking it completly down to shim. But I have options. Can certainly use a jack and jack up the stand and shim, I can jack up the 3/4" plywood the tank is sitting on on top of the stand and shim there. The stand is a steel box tubing structure. Or I can go into the crawl space below and jack the floor that is under that part of the tank...or finally I can DO NOTHING.
I am really convince doing nothing isn't going to do anything to the tank. If the tank were so poorly constructed that having it off balance would create such a load difference that failure were iminent then I think there would be a lot of posts on here starting off with, "I came home from dinner and my entire tank was shattered on the floor.
So I hate people like me who start a post with a question and then answer it themselves...but I am really interested in hearing some feedback.

 

[flower]

You can jack up the floor from the crawl space???
The first thing I had done when I moved was double check the strength of the floor where the tank will go.
The idea that the tank has been unlevel for so long it is no problem...an inch is way too much so I think you should empty the tank and fix the problem. That is the right answer...what you do with the advice is up to you.

 

[stimpy4242]

I am not sure the question you are asking in your first line...The stand is on the first floor, below the first floor is the crawlspace. So I could put a jacking column directly under the subfloor where the tank is sitting. So that is an option.
It might be important to note that the tank itself sits on top of 1" of styrofoam board to make up for an imperfections, that sits on top of a 3/4" piece of plywood. So the tank itself is perfectly FLAT which of course is different from level. Now people will argue the reason why an unlevel tank is bad is because more weight is being applied in one area over another, but I argue that if I were to simply raise the level of water in the tank then now its holding even more weight than before. So the amount of "stress" that is applied to one area versus another is trivial. The tank is made to hold up the weight.
I just feel like people only assume that the tank should be level...which makes sense all around, but it doesn't mean that IS THE RIGHT ANSWER. An engineer might come in and say, that tank could take 10x more the weight than it currently has so then it is perfectly acceptable to have that weight in there.
Still looking for advice as to where the shims should be done...under the plywood, under the stand, or from the crawlspace.

 

[flower]

Quote:
Originally Posted by stimpy4242 http:///forum/thread/384667/unlevel-tank#post_3370607
Well after the move, it has become clear that the new house is not as level as the old house...
In fact from front left corner to back right corner there is a height difference of about 1". Now I have read plenty of posts on here about unlevel tanks and how everyone says this creates a ton of stress. I am curious if this stress is any worse than if the tank was just full of water and nothing else. Also most of those posts have somoething say, well its bad, but mine has been unlevel and I have had no problems.
The tank is completely setup at this point and I am definitely not breaking it completly down to shim. But I have options. Can certainly use a jack and jack up the stand and shim, I can jack up the 3/4" plywood the tank is sitting on on top of the stand and shim there. The stand is a steel box tubing structure. Or I can go into the crawl space below and jack the floor that is under that part of the tank...or finally I can DO NOTHING.
I am really convince doing nothing isn't going to do anything to the tank. If the tank were so poorly constructed that having it off balance would create such a load difference that failure were iminent then I think there would be a lot of posts on here starting off with, "I came home from dinner and my entire tank was shattered on the floor.
So I hate people like me who start a post with a question and then answer it themselves...but I am really interested in hearing some feedback.

I would think if your floor is sagging and making the tank unlevel so that you can go under and jack it up...you need to reinforce it ASAP. That is what I meant by my first line.

 

[aquaknight]

Are we talking the 185gal? You could probably clock a well made 29gal at a 45° angle and it wouldn't fail, but a large tank is of concern, IMO.
Couple random thoughts...
It took my 240 6 months to fail (tank construction issue, not off level). 4 months in one house, then we moved, and 2 month in the new house before the braces let go.
How is the tank constructed? Glass with plastic rim? 1" of styrofoam is only going to accentuate being off level. It's physics. The lower side of the tank has more water, so it weighs more and pushes down into the styrofoam harder, and becomes even more off-level as the styrofoam gives more on that side.
If the tank is 6 or 8 feet long, I wouldn't shim it. I believe it was 2Quills who mentioned it, but shimming a long tank only on the low side, would cause the center to sag.

 

[stimpy4242]

@Flower - The floor has already been reinforced to prevent any more settling. It is a waterfront home on a crawlspace and it was never waterproofed...so we dug the trench added drains and sump pumps and then pour 19 concrete footers and ran two steel I beams the length of the house with 19 jack columns...so while the floor is sagged from preivous settling...it is going no more. When I say I can jack it up, is that I could put a targeted jacking column and raise up that part of the floor..in theory. I know the hard wood slopes down toward the wall that has settled, magically probably about 1". I can probably jack up the floor at this point, but have no effect on the wall...of course that assumes I do about 1/8" every day or less.
@AquaKnight - I am with you on the styrofoam, that does probably make sense. And I guess you are right about the shim under the tank, best to go under the stand or the crawlspace. Thatnks for that advice, I completely agree with you that putting a shim under a corner of the plywood, will eliminate the contact with the center supports and side support and allow sagging in the middle even on a 3/4" thick piece of plywood, especially with high humidity.
So now we are down to shimming under the stand or under the floor. Any more advice on one over another. As odd as it sounds shimming under the stand will be slightly more difficult as I will need to install to jacks on the stand to raise it up off the back part of the floor which means puttting a 4x4 piece of lumber under the top section of box tubing...

 

[geoj]

Flood Detective Pro