leveling a tank stand

[Bryopsis]

The foam works great, the difference, it supports the entire bottom of the stand and gravity levels it.

Talk smack if you will, sounds like some need to brush up on their physics
(you will not experience stress on the stand and tank like you will with shims; look it up)

It follows that any force applied to one part of a solid object must give rise to internal reaction forces that propagate from particle to particle throughout an extended part of the system. With very rare exceptions (such as ferromagnetic materials or planet-scale bodies), internal forces are due to very short range intermolecular interactions, and are therefore manifested as surface contact forces between adjacent particles — that is, as stress.

http://en.wikipedia.org/wiki/Stress–strain_analysis#Uniaxial_stress
http://en.wikipedia.org/wiki/Stress_(mechanics)
http://www.engineersedge.com/material_science/stress_definition.htm

As far as the comment about mold under the tank, sounds like a personal problem with keeping it in the tank. The carpet under the tank will dry from the principles of fluid dynamics and being surrounded by a dry carpet. (same principle as phosphate leaching from rock; perhaps that's more understandable to some)
That's the reason to have carpet for one, but realistically it sounds like a stretch to push shims.

If you think a little air under the stand helps, that's great, but you just further prove my point about structural stress. If all of the bottom of the stand is not supported, or at least supported in a patterned way (think tiled floor) it will develop stress over time at the gaps. A shim creates these gaps, and I guarantee over time, the shim will warp or the stand will. This stress travels up the stand and the stand is no longer flat, it's structural integrity has changed. The tank surely won't like that as it tries to warp with the stand.(glass doesn't warp so well)

Next time you buy a used stand, think about it when you put it on a level floor and it doesn't sit square.(the other person probably used shims)

 

[SGT_York]

Memory foam does not have the compaction strength required for any kind of real weight. It certainly wouldn't stop the tank from rocking as the areas with the most gaps will have the least amount of compaction. So problem 1.

Problem 2 the water entrapment. water will diffuse but when in contact with solid wood under the stand the wood will naturally absorb water making it a long drawn out process to dry. The carpet does the same thing so the two mixed can lead to a mold problem. Just try drying out your basement carpet and underlaid pad without removing the carpet. It doesn't work. If you are like me and spill a bit of water with a change it will lead to problems. There are plenty of pictures of solid plywood tank bottoms with mold on the carpet for evidence if you care to look.

About structural stress I am assuming that the OP used Rocket Engineer's template (as mentioned in the top post) so there is a 2x4 along the bottom that will support the weight, that means the bottom does not need to be supported. The only portion of the tank that needs the support are the vertical posts. the 2x4 will provide it's own support and supporting it provides no benefits. the time it will take for that 2x4 to develop structural problems will be well outside our lifespans. Lastly the sand would not warp as adding the shims corrects the problem, if you skimped on the supports under the vertical supports then you will have downward stress on all the joints which will lead to warping.

Two cavitats if you have a solid plywood bottom with no dimensional lumber there may be an issue, depending on the thickness of the ply and width of the tank. Also if your tank is on a wood floor (crawlspace or second story) you may need to reinforce the weight distribution so the weight is not distributed solely in four locations. If it's on concrete you are great even if there is carpet between.

 

[davocean]

Foam will do nothing other than ride the floor as it is, and maybe possibly help w/ any minor deviations, it will not level the tank.
Most of us have shims under our stands, as most floors are not perfectly level.

 

[Bryopsis]

Memory foam does not have the compaction strength required for any kind of real weight. It certainly wouldn't stop the tank from rocking as the areas with the most gaps will have the least amount of compaction. So problem 1.

Problem 2 the water entrapment. water will diffuse but when in contact with solid wood under the stand the wood will naturally absorb water making it a long drawn out process to dry. The carpet does the same thing so the two mixed can lead to a mold problem. Just try drying out your basement carpet and underlaid pad without removing the carpet. It doesn't work. If you are like me and spill a bit of water with a change it will lead to problems. There are plenty of pictures of solid plywood tank bottoms with mold on the carpet for evidence if you care to look.

About structural stress I am assuming that the OP used Rocket Engineer's template (as mentioned in the top post) so there is a 2x4 along the bottom that will support the weight, that means the bottom does not need to be supported. The only portion of the tank that needs the support are the vertical posts. the 2x4 will provide it's own support and supporting it provides no benefits. the time it will take for that 2x4 to develop structural problems will be well outside our lifespans. Lastly the sand would not warp as adding the shims corrects the problem, if you skimped on the supports under the vertical supports then you will have downward stress on all the joints which will lead to warping.

Two cavitats if you have a solid plywood bottom with no dimensional lumber there may be an issue, depending on the thickness of the ply and width of the tank. Also if your tank is on a wood floor (crawlspace or second story) you may need to reinforce the weight distribution so the weight is not distributed solely in four locations. If it's on concrete you are great even if there is carpet between.

If a rocking tank is a possibility, why does mine not rock? Also bringing up compaction issues is moot, we're talking about memory foam being crushed under the weight of the tank and it will level because of the resistance to compaction. (2 1/4" memory foam pads underneath will not resist 800 lbs enough to allow for movement, but it will allow for a solid base to conform to the absence of leveled surfaces between the floor and the tank stand)

If water entrapment was a big issue, nobody would use the stands we do. Again though, water is not meant to be under the stand, and a 2mm gap by a shim won't change the mold factor. (it would only help stress the stand)

You talk about the way the braces are positioned in the stand, but the reality is, we're talking about 1,000 lbs on average at least. So for most scenarios, the stress would relocate someplace. Perhaps right to the shim. You might bring up that 2x4's won't warp, but unless you're using steel shims I bet the shim would.

We can dance around this all day long, but you talk to a structural engineer about supporting thousands of pounds of weight, and using shims to make up for the lack of a square foundation, they'll probably laugh at you.

But good luck to the OP! There's many ways to do it, but like all aspects of this hobby, everyone has a story, and all shims create a gap....

 

[Bryopsis]

Foam will do nothing other than ride the floor as it is, and maybe possibly help w/ any minor deviations, it will not level the tank.
Most of us have shims under our stands, as most floors are not perfectly level.

It won't level the tank?!

Boy, my setup must defy physics!

FWIW, you put 1 layer on the floor, and 1 layer halfway under the tank on the side that needs elevated.
But again, my setup MUST defy physics from the experts' opinions here. :|

Cheers! (and no, I'm not going to check responses because I feel flames coming on; as always on US forums lol)

 

[Bryopsis]

Sorry guys, do what you will, I can't stop laughing so I better stop reading responses before I bust a gut! lol

 

[davocean]

Yes, thank you so much for schooling us all, now all of our tanks can finally stop crashing to the floor...:hmm4:

 

[reef tank 2.0]

oh dear, what have i done?

:headwally:

 

[davocean]

oh dear, what have i done?

:headwally:

Absolutely nothing, it happens, once in a while someone new comes on w/ the need to tell us how we have all been doing everything wrong all these years.

 

[rcmania]

I have used both wooden and composite shims. I have to say the composite shims seem to work just as well as the wooden ones. I like the composite shims better as they snap a nice and neat line. With the wooden ones I had to clean up. My composite shims are holding my 220 up with no problems. I just used a couple to level the stand out then I went around filling in the gaps to make sure every part of the stand was supported. I also inserted the shim on both sides of the stand until the shims met the stand bottom. If you need to come up an 1/8th of an inch I dont think you will need to insert from both sides. But if you have to come up a quarter of an inch then I would do the double sided method. My tank has been up a year now and has not moved out of level. The tank water will tell the tell with this. Just turn off your pump and check the water level with the trim of the top of the tank.

Just my two cents.

 

[rcmania]

Oh and please dont use the foam method.

Think of your tank as a house that you are building. Would you build it on the top layer of ground or would you dig to solid ground for a footer? you want that hard contact when dealing with this type of weight. It may last a little while but over time you will have issues.

 

[woodnaquanut]

FWIW, you put 1 layer on the floor, and 1 layer halfway under the tank on the side that needs elevated.

That just seems like another version of a shim. You're just using a big squishy shim!

I'd love to see a pic of the foam/stand.

 

[reef tank 2.0]

ok, i really need some advice here.

I bought some composite shims as we discussed. I started sliding them in and the gap that ended up needing filled was a good quarter inch.

so, after moving it around on the carpet, thinking it might be the floor, there was no change. So I slid the stand into the kitchen where i knew our floors were level. again, no change.

so i decided to place my framing square in the stand at the end where it was "off". I see the spot that is causing my heartache.

so the question is this. is this 1/4" gap enough to cause me problems or will it be ok for me to place the tank on? The bubble on my level is not THAT FAR away from true, but enough to not be centered. Do I need to redo this stand?

here are some pics.

 

[reef tank 2.0]

any help on this?

 

[davocean]

Hard to say what to do from just the pics, one thing I always make sure to do when building a frame is check for square by measuring corner to corner and making any corrections during the build.
After glue is set up and you have it painted and everything it can be difficult to correct.
I would have to have it right in front of me to see how to correct it really.
Obviously if you can not get a level surface a correction of some kind is needed.

 

[reef tank 2.0]

well, let me see what kind of trouble i get in to when trying to take apart that area of the stand. If my 2x6 are slightly warped at the base, that would have thrown off the vertical support angle. this could turn in to a chain reaction. where i keep having to search and search in hopes of finding the bad board. well, back to the unbuild/rebuild.....sigh

thanks for the response

 

[davocean]

Measure corner to corner in each direction and make sure/check for square, if you find numbers don't match that will help you figure which way to rack it, if that is the issue(I would suspect.
You might get lucky hopefully.

 

[woodnaquanut]

any help on this?

It's really hard to see what's going on from the pics.

How are the other corners? Have you checked to make sure your square is, well, square?

As Davocean said, measure the diagonals of the whole stand. If they are not equal, you have a parallelogram instead of a rectangle.

 

[rcmania]

Like stated above its hard to see what's going on. Are all boards cut to the correct length. This to can make it seem it's out of square. When I put the back on a stand I use the two factory edges to square everything up then cut the excess off leaving a quarter inch over hang. I then use a flush trim bit to trim it flush. But this only works if all the boards are cut to the correct size.

 

[reef tank 2.0]

I would like to say my boards were cut to the exact/correct length. That's what tends me to believe the board could be twisted/warped. I will be tearing the trim off and skin and see what I can find......please stay tuned.