Do i need to Shim...?

U

uvijaya

Member
I am setting up a 240G glass tank on a prefecto deep dimension wood stand. There is 1" thick styrofoam between the tank and stand. The tank dimmension is 60" L X 36" W x 26" H and the stand is flat stand with no legs. I am placing the tank in the basement and its laminate with padding underneath and then concrete below it.

As i filled water into my tank yesterday, i stopped at 5" of water in the tank and measeured the back and front water level. The back of the tank is 0.25" higher in water than the front.

Should i continue filling as the water level will stabalize or should i shim the stand?

Thank you.
 
His sounds like a unique situation(mentioned no legs) and sounds like this is on concrete or block wall?
Not positive, pics may be needed on this for best advice.
Also, does tank have trim?
That foam could be too thick if it does.
I would definitely level it.
 
Do you have an inch thick piece of styrofoam between the tank and stand? I would be concerned about that if things are not completely level.
 
why is there foam between the tank and stand? not sure i understand the purpose of that. Also, I'd remove the laminate and padding from under the stand. That also could be a source of the unlevel stand if it's compressing at different amounts under the stand.
 
well i spoke to my roommate (he's a general contractor). he said that the flooring isn't the problem, as the padding under the laminate is a high density foam, is only about 1/4" thick, and will always compress evenly. His thought is that either the floor isn't level, or the foam between the tank and stand are the issue. If it's the floor not being level, he says you'll have to shim the entire stand so that there isn't any load bearing areas that aren't on solid ground. If there are, it could cause some major issues with your tank down the road. ie: your tank could crack, or pop a seal.
 
I checked the level of the stand it was unlevel from front to back, not side to side. Furthermore i checked the level of the floor and turns out its the culprit, because i have laminate floor and underneath the laminate i have padding and below the padding its concrete, i think the concrete is also not in level since its basement concrete and the builders make sure if there is a flood the water moves towards a drain in the furnace room. Its not noticeable but this is whats causing the quarter inch rise of water in the back of the tank.

If the floor is not level, what can i do now? Still shim the stand between the floor?

I will take some pics tonight.

Thanks
 
<a href=showthread.php?s=&postid=15393560#post15393560 target=_blank>Originally posted</a> by Jorober
well i spoke to my roommate (he's a general contractor). he said that the flooring isn't the problem, as the padding under the laminate is a high density foam, is only about 1/4" thick, and will always compress evenly. His thought is that either the floor isn't level, or the foam between the tank and stand are the issue. If it's the floor not being level, he says you'll have to shim the entire stand so that there isn't any load bearing areas that aren't on solid ground. If there are, it could cause some major issues with your tank down the road. ie: your tank could crack, or pop a seal.
Click to expand...

This is good advice. I dont like the foam between tank and stand. It could compress unevenly and cause problems.
 
Standard drain slope in a sub-grade basement is 1/4" per foot. Since you're only 1/4" over three feet, and it's evenly out of level (it's not sloped a 1/4" on one end, and 1/2" on the other), which you said it's level side to side so it should be. He said don't worry about it unless it's bothering you. His tank is on a sloped concrete floor, and it doesn't bother him at all. If you want to shim it, you need to make several shims to go under the tank pointing towards the back to level the whole thing evenly. The other option is to tailor the stand to match the floor. Really... it's going to be a ton of work either way to level it and not cause a bigger problem than a tank leaning 1/4" over 3 feet.
 
I'd get rid of the styrofoam for sure. That could cause some issues down the road with the seals on your tank, and I'm unaware of any benefit to having it there. If you're using it as a spacer, I'd recommend using two pieces of 1/2" plywood cut to fit the stand perfectly.
 
I have a 300g and the front is about 1/4" different then the back. It is on a concrete floor and has been up 3 years with no issues. I would be concerened with shimming the type of stand you have that you would put stress where it shouldn't be....
 
It's always been my understanding that if you have a stand that isn't exactly level then you would need styrofoam so that it would compress further where the extra weight is. A lot of the larger systems I have seen use styrofoam. Me and a freind set up his 120 gal tank that was put on a homemade stand that was sitting on a somewhat unlevel tile floor. We shimmed the stand the best we could and got it sitting as firmly as possible and then put 3/4 inch foam insulation between the stand and tank to even out the pressure as much as possible. I thought the idea behind foam is that it would compress unevenly to reduce stress on the tank.
 
there shouldn't be any stress on the tank as long as the slope is only in one direction. The slope will be 1/4" all the way up, so there will be insignificant pressure differences on the seams of the tank.

I understand the idea that the foam could compress unevenly to level itself out, however I don't believe that it would do that. I'm thinking of the physics at work here. If you consider the psi of pressure being applied to the bottom of the tank you will understand my point. If the tank front is 1/4" lower than the back, then the front will have more water in it as it fills up. Thus there will be slightly more pressure applied to the foam in the front of the tank, than the back of the tank. The pressure difference will remain the same as the tank fills up to the top with water. The back would never sink more into the foam than the front as there is less pressure being applied by the water weight. Therefore the tank would still be unlevel front to back. The only way to level it would be to force it physically to compress the back more. One could force it to compress more in the back by applying more weight back there, like adding live rock. Now there would be more weight in the back than in the front. How much would depend on the weight of the rock. This could cause the foam to compress more in the back than the front with sufficient weight. However, the tank could end up lower in the back after all is said and done.

So I still think that taking the foam out would be a better option. Eliminating all variables you have controll over will help you be more successful.
 
I would like to thank everyone for their inputs, i never thought i would get this much advice. :)

Jorober - so i dont need to do anything, if the water level is 0.25" difference?

The stand already has a .5 inch plywood on top of it, and i used the Styrofoam on top of that to balance the weight evenly.

This is the stand:
http://www.reefsolution.com/catalog/product_info.php?products_id=1855&language=en

I also was under the same thought of what GrimReefer82 is stating. So Styrofoam is not necessary?

Thanks
 
It would actually be very easy to shim. since tank stands bare all their weight on the perimeter, you could buy some 1/4" stock....like lattice stock, which is like 1/4" x 1 1/2". cut it the length of the stand and slide it under the low side (you said the water in the back of the tank is higher, that means that is the low side). Once you get this shim under the stand, the stand will be contacting the floor in the front and ramping up to the 1/4" shim in back. Use some tapered door shims to fill this void on both ends. With this done, the perimeter of the entire stand will be stabilized and youll be much closer to level.

With that said, 1/4" isnt terrible. Shimming it would really just be for peace of mind. I would shim it.

I dont know too much about the foam theory, but 1" seems aweful thick to me.
 
Jbird69, how many pieces of shims i should be sticking in the back and how far part? its 60" in length. I have read in several places about the Styrofoam usage, so none of you are using the foam?

Thanks
 
Well lets say one corner of the stand was slightly higher than the other 3 wouldn't you think that the 1 corner would compress more? I understand that this probably wont help with front to back leveling or even end to end. I just thought it could relieve stress on a corner.
 
You want the shim to be continuous. You should be able to find lattice stock at a local lumber yard...mayde even HD. It is 1 1/2" wide by 1/4" thick and it comes in lengths of ???? 4'? 6'? 8'? something like that. Or you could just get a sheet of 1/4" masonite or something and cut it into strips. The result you want is a CONTINUOUS shim under the low edge. Then fill the tapered gap that will be left on the ends of the stand with tapered door shims.

I cant comment on the foam theory cause I dont know about it. I dont like the thought of something as heavy and valuable as a reef tank sitting on anything that isnt absolutely solid.
 
Nope. No styrofoam on either my 180G or my roommates 330G tanks. Both slope about 1/4" and we've never seen any issues. My 130G sloped 1/2" over 22" front to back, and there were no problems with it either. I'd just fill it and forget about it.

Jbird69, you are right, the weight of the tank is on the perimeter in a glass tank, so there shouldn't be much to worry about in the center of the tank. But you would have to shim down the sides, and across the front of it. Then you'd have all these little shim edges under your stand. Most people wouldn't notice, but being that I used to do finish carpentry with my father, it'd drive me nuts. And look very unfinished. I think it would be more of a pain to shim it than it's worth in my opinion.

Uvijaya, you could go either way really. shim it or not, I don't think you'll really have any problems with it. It all depends on your preference, and and what you can or cannot live with.
 
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