Leveling a big tank

[Steve]

Question about leveling big tanks. Now that the office is about done I'm starting on working in the tank this evening. So first thing was to fill it about 1/3 full just to clean all the grime out of it. In doing this I noticed it is a bit unlevel. This is a 7ft long 265g tank on a very sturdy wood stand (you could sit a car on this stand) and it is off by about 1" over the 7ft span. The reason is the concrete floor in the basement is 50yrs old so it is not perfectly level.

I was thinking of shimming it but I'm wondering if it would be safer to not shim it. Because the stand has 7ft lengths of of 2"x6"x7ft wood running the length of the stand, so if I shimmed it it would be hard to shim without putting pressure points into it. So I'm thinking maybe it is best to not shim it. I've been searching online and found everything from people saying long tanks are fine being out of level 1" to people saying it's a big problem.

Any feedback from you guys on this one please?

[Marty]

I used shims on my 400 gallon.

[Steve]

How far apart did you space the shims Marty? I just want to make sure I don;t throw in any sort of pressure point at all or have a part of the stand unsupported by improperly shimming it since I have never done it before.

[lilscoots]

For my 6' 125 and for my 180 replacing it, the floor drops a half inch where the tank sits.  I put a piece of 1/2" plywood under the low side that was roughly 6" wide.  I built my stand though and the main supports are in the corners I thought about putting shims under the middle supports but never did for the 125, I may for the 180.  I would definitely level it though.

[Steve]

Here is a pic of the back of it so you can see how the stand is built. So if I was to shim the one end of it about 1"....what would I do with the rest of the stand such as in the middle because then that would be unsupported and off the ground. Would I just have to buy a ton of shims and shim it every few inches? Also what type of shims would be best because this will be around 2500lbs when filled with water & rock.

[Marty]

I would take a piece of wood and have a graduated shim traveling the length of the gap.  So if at the center you have a 1/8" gap, and at the end you have 5/8", measure the distance, mark a piece of 2x4" with a chalk line for the graduated angle, and cut a piece to custom fit.

If you don't trust that, you could always go to a steel supply shop and get a bunch of metal shims (like what you would put underneath I- beam stanchions to stick underneath the entire length.

[SirBailey]

Better to level the tank so there is no extra side pressures on the tank.  I use 6" composite shims and planks to level my tanks.  They are waterproof and do not compress under pressure.  Level the tank at the four corners and shim under all the vertical pillars and you should be good.  I have double stacked 120's that only have 5 legs contacting the ground.  They have been set up that way over ten years.

[Steve]

Thanks guys I appreciate the info. This is one of those "WTH was I thinking things" because I didn't even think to check for levelness until it was all built into the wall and such....duh duh friggin DUH I amaze myself sometimes

I was just down there and removed some nails/screws and supports from the wall and stuck a jack under the one end of the stand and was able to get it raised a good .500-.625 without damaging the wall or having to to too much tear down. Still need to find another .500 worth of room in it though. Probably going to try making some long tapered wood shims tomorrow and see how it goes.

[TrailerParkFishTanks]

home depot sells bundle of contractor shims or door shims for pretty cheap. if you want to avoid excess pressure in certain areas i would level corners as needed then insert shims at intervals down the length of your bottom. then all you have to do is snap off the excess shim that sticks out. the weight will be distributed well enough to avoid any sagging  or twisting in the stand.

[danielratti]

We just build a 250 from the stand to the tank and we shimmed every 2 inches and it worked out pretty well. You don't need anything too fancy. We had a 300 we moved and set back up in the guys new place and needed to use 2x4's to shim up one end of the tank.

[Ron]

home depot sells bundle of contractor shims or door shims for pretty cheap. if you want to avoid excess pressure in certain areas i would level corners as needed then insert shims at intervals down the length of your bottom. then all you have to do is snap off the excess shim that sticks out. the weight will be distributed well enough to avoid any sagging  or twisting in the stand.

x2. That's what I've done in some cases.

Another option is to build a level floor atop the concrete floor. My "fishroom" was/is a bedroom built in the basement. To help retain heat it was built with a ~1/2"-3/4" floor overtop the concrete that not only insulates, but helped level that particular room.

[Steve]

Going to head to Lowes in a bit to pick up a few packs of shims/wedges. Okay here is where I am at today guys, I'd like you're thoughts on this now. I jacked up the low end of the tank and it ended up taking a 2x4 under the low end to get it level. Now with the one end of the tank shimmed up about 1.5" it sits pretty level from one end to the other with maybe about 1/8"- 3/16" difference over the 7ft span. That should be well in the range correct?

The other thing is now that it is leveled side to side it is maybe 3/16" - 1/4" off over the 2ft width front to back. But it is off exactly the same on each side front to back which tells me it is not tweeked at all. I really don't want to go messing with trying to shim the front to back and mess up the fact that it is currently not tweeked/twisted at all so would I be good now just to get the shims and brace up under the bottom of the stand now without trying to mess with how it sits any more than I already have?

Here is a pic so you can see how off the floor was 

[Ron]

I almost hate to ask, but how does this play into the wall opening you made for the tank?

If you have access to a table saw, you might be able to shave additional 2x4s to help shim the bottom.

The end to end difference you've found after leveling isn't a big deal. I feel like almost all of my larger tanks end up with some tiny level of difference. Front to back, 1/4" doesn't seem like a big deal, but starting to go over that raises my concern a bit. If you haven't yet, you should get some sheets of closed-cell foam to set the tank on. This will allow the tank to "self-level" a bit and help your numbers even more.

Leveling a tank is certainly important, but even more important is supporting the bottom (edges on a glass tank - entire bottom on an acrylic tank) evenly IMO. Torsion will much more easily compromise seams.

[Steve]

I almost hate to ask, but how does this play into the wall opening you made for the tank?

Actually it made it fit better. When I did the opening in the wall I based it on the floor being level across so the tank actually sat 1" off inside the wall itself (now I know why lol). So now that I raised the left side it actually fits much nicer in the wall and wont take anywhere near the size trim to hide the edge, so that worked out for a positive luckily

It's for sure no more than 1/4" front to back, probably closer to 3/16" actually. It sits nice and flat on the stand. The whole top of the stand is flat and the tank sit's really well and evenly on it so I think I am good for not having any twist right now. Been looking at shims and the wood door jam shims kind'a scare me for durability over time with this much weight (probably be fine but I'm a bit OCD lol) so I checked out the Composite ones someone mentioned and those say they hold 16,000 of weight so I think I am gonna go buy about 6 packs of those to use.

[TrailerParkFishTanks]

i would shoot for no more than 1/64" when leveling. (j/k) when leveling multiple directions i find the tinker and test method to work the best, if you know anyone that works in a fabrication shop or metal shop they'll almost definitely have metal shims if the door shims scare you. they'll also be more accurate. if you dont know anyone in that line of work PM me. i'll help you out. im in wixom.