styrofoam under tanks
 

My new 180 has arrived! I built my stand and have checked it for level and square. The tank I have has a flat trim on the bottom not the trim that raises the bottom pane of glass 1/2 inch. The bottom pane is only raised the height equal to the width of this flat trim probably 1/8 of an inch. So I want to know what I should place on top of the stand between the stand and tank.
Couple of ways I have considered and have been searching online about.

1) I could place the tank directly on the 2 X 6 rails nothing between tank and stand with open top tank.
2) place plywood on rails and tank on plywood
3) place 3/4 styrofoam on rails then tank on styrofoam
4) place plywood on rails then styrofoam then tank

Any suggestions which way would work best or what way do you have your large tank placed. Take in consideration the type of trim on the tank. Thanks
Please post with anything you have experienced. I know it has been debated a lot but I want to do it right.

Option 4, plywood, foam, tank. Double check plywood for level prior to adding the foam.

I use 1/2" rigid styrofoam under all my tanks, I don't like to use thicker stuff. Sometimes I have to look around to find it with straight edges instead of beveled edges, but I can usually find it at Home Depot. The stuff I buy is Owen Corning "Foamular". I like the styrofoam to stick out around the tank about 3/16" all around, so since your tank is 24" wide I would cut the styrofoam down the middle of the length and leave a little gap in the middle so it can stick out all around. Using plywood helps to strengthen the stand if there is any doubt, but usually is not needed if the stand is well built and the edges line up nicely. Although if the bottom pane of your tank ever breaks the plywood helps to hold the water in a bit while you're panicking to get everything out. :D

Is this what you have for your tank?

Thanks Myka. From what I have been reading the opinions are foam under tanks without a trim and no foam under tanks with a trim. The trim I described in my first post is not the "normal" trim that I have seen on other tanks. The bottom pane of glass would almost be resting on plywood if I used it. So would this be considered trimless? Tanks only need to be supported on the outer edge correct? I'm thinking if I use the styrofoam without the plywood it would even out any imperfections in the 2 X 6 while not putting upward pressure on the other sections of the bottom glass. Anyone see anything wrong with this? From what I can tell the sides of the tank are sitting on the bottom glass. Thoughts?

Option 4, flush with tank edges, 1/2" pink.

I was hoping you would reply. This is what you recommend on your stands? I realize yours are metal.

I use foam under both types.

This is what I do with ALL my tanks regardless of how there made. Wood or metal I use 3/4" plywood on the top , then 1/2" ridged pink styrofoam. I like to put a molding around the bottom of the tank as well to hide the foam & bottom edges of the glass.

Good info thanks.I was thinking I would use foam just wasn't sure of which option. I have the white polybead styrofoam I guess I'll pick up some of the pink rigid tomorrow.

+1, I would even go as far as to a double layer of 3/4" plywood to make sure its nice and stiff

Steve

Me three....

Steve

This is not good, you deffinately want to have plywood then foam to support the WHOLE bottom pane so it doesn't crack.

Fwiw, the foam comes in pink, blue, or purple depending on brand. I have all three colors. :lol: As long as it is rigid styrofoam you're good.

This is what it looks like (these are small pieces):
http://aislamiento.com/images/produc...OAMULAR400.jpg

Got the correct foam now thanks Myka. Grizz why do you say this? I had to replace a front pane of glass in a 125 and if I remember correctly the sides were sitting on the bottom pane. It was a while ago so I may be mistaken. I thought it would only need to be supported by the outside edge as with other tanks.

With the sides, front and back glass sitting on top of the bottom pane of glass there is way more chance of the tank cracking under the weight of the side glass. All it take is to get one corner a little higher then the rest and you have a stress point. make sure that the bottom of the tank is sitting perfectly flat EVERY WHERE. A properly built tank has all side on the outside of the bottom pane, its called a floating bottom.

i thinn the 180s are built like koles i just took off my broken piece of glass and found that it too sits on the bottom pane.. not sure why they did this with 180's but thats what caused me to make a measurment mistake of 1/2 inch.oops but i too will be doing plywood then foam then tank.

Hmmm...I don't have any tanks designed like that. Maybe ask a tank builder for their opinion?

Most standard tanks from builders have the sides on top. The other method is actually more of a DIY thing that some custom builders do as well. Professional builders will make sure the glass is flat and has enough silicone in the seam so the glass will not chip. For exceptionally large tanks above the standard you see more of the base within approach as the glass is thicker and heavier but these will also come with specific requirements regarding supporting the entire tank area.

The reason why the "sides on top" method is used is it can be supported by the standard trim around the edges and doesn't require full support under the entire tank area. This works better with standard stands and eliminates the need for foam or other layers between the tank and stand. Despite what we all believe to be better practice, placing foam between a tank with trim and the stand is not required.

Thanks lockrookie I thought I had seen this before on a 125.

Sphelps I have read something like this on an old thread on another site. It was posted by a person who was said to be in the aquarium building industry with a larger company. glass less than an inch can be placed on top of the bottom pane.

I have read so much my head hurts lol.. My only concern with supporting the tank with plywood and then styrofoam is the bottom of the tank is almost flat it is only raised by the 90 degree angle piece of plastic trim. So when the edges of the tank sinks into the styrofoam the bottom pane will have upward pressure placed on it by the styrofoam. Thoughts?

I'm confused. All of the store bought tanks I've had are raised bottom pain with the four sides surrounding it, black trim over that. I've fired them on a million different things without foam. Most makeshift stand bow in the middle and I've had many tanks where I could slide a card under the center of the tank. I'm not saying this is good, but I've never had a tank leak. I usually just try to find a stand that is pretty darn flat.

If you add foam to this kind of tank it shouldn't push on the bottom pane.
The bottom is supposed to float and be supported by the trim. I've actually seen a tank that was half over a flat bar top, lengthwise, and the two floating corners propped with 2x4s on end. Once again, bad bad idea, but the point is you don't support the bottom and you would be hard pressed to blow a tank supporting it by a couple points on the trim as long as they are flat and level to each other. A leak would be caused by twisting or torquing the tank.

Custom build tanks/ quality tanks generally have the sides sit on top of the bottom pane. Smaller tank go on a rubber-esqe mat on a flat surface. Large tanks on a very flat surface followed by 1/2-1" dense foam (not the white stuff) and then the tank. Usually it's fine to remove the support material around bulkheads within reason.

Have a high point with this tank and you could cause the pane to crack.

That sounds about right, 1/2 is pretty much the thickest used for "standard" tanks, the biggest being around 230gal.

Your plan sounds fine, if the foam compresses enough so the bottom pane makes contact no worries, any pressure the foam applies to the glass is normal to the pressure from the water weight so it actually subtracts not adds. In other words the pressure from the foam is a reaction and will reduce the load on the glass. If the stand is perfectly flat and supports the tank trim without any gaps then foam isn't required, it really doesn't hurt though so if it doesn't bother you might as well use it.