what is the truth

[marinelife]

I purchased a used Acrylic Tank with stand. I setup the tank and it is filled and running but I have seen a few other tanks and got to researching. From this research I found out the tank stand should have had a board on the top. Right now the tank is just sitting on the stand. The stand is made like a floor with supports running front to back, on the ends there is a 20" gap between the supports and then about 14" between them and the center support. Is this ok for a 1" acrylic tank. The tank came from a LFS that does most of the sercive tank in the area and the tank has been sitting on this stand for years. Do acrylic tanks really need 100% support, is so do I need to take this down and add a board or maybe just add some more support under the tank. What problems could I run into with the stand as it is. The tank is 375gallons with 1" acrylic all the way around.
Picture before I added the tank

 

[LakeEd]

I have always heard that acrylic tanks "require" full support under then, because the acrylic "may" sag. I don't have any prof on this, just what I have heard and believed...but we all understand how in our hobby, rumors can often be untrue...so I'll be following along with you on this.

 

[northstaraquatics]

I'm not an expert! It should be fine. That said, Any uneven points on the stand could cause a stress crack. I also feel that you really don't want to add any supports underneath with the tank full. 1" is not realy going to bow.
If it were my tank, I would go for the piece of mind and drain it and add the plywood. I had a 125 on a metal stand with one center brace. I was surprised it never let go. If you go for the plywood, make sure it's ACX (smooth on one side).

I lastly would contact the manufacturer or any tank fabricator to get their recommendation.

Jon

 

[marinelife]

Thanks for the replies. If I just had water only in it I would do it in a heart beat. I have about 1000 pounds of rock and all my corals, clams, and fish in it. I guess if I pulled together some tubs I could just move everything out and then back in. I will see if I can get an tank fabricator to answer me as I have no idea who made it

 

[Meche]

How deep (wide) is the tank? How tall?

If you want a real answer I can run the numbers for you. You basically have a simply supported, uniformly loaded beam made from 1" acrylic.

My guess is that you will be fine even if you consider creep (deformation over time due to a load). But a plywood board across the top would help.

 

[marinelife]

96x30x30 any help would be great

 

[Meche]

So your biggest span would be 30" front to back. Minus the width of two 2x4s (1.5x3.5s right?) so maybe about 27" by 20" is your biggest hole, right?

And there is 30" of water above it right?

 

[marinelife]

that is right, the wood is 2x6s with the tank sitting on the 2" (1.5") side

 

[chadmace]

You said "and the tank has been sitting on this stand for years" Was that with water in it?

One thing you may want to think about is.....If there is even a little bow already forming under the tank adding a board would be asking for trouble.

 

[marinelife]

It had water in it, that is a good thought, i am not sure if it is straight across the bottom or not, I would guess not but I do not know for sure.

 

[northstaraquatics]

In your case I now would suggest to leave it be. The 125 I talked about earlier was only 3/8" and was fine with more than 1" of bow. I had it full for more than 10 years and 5-10 moves...

Still contact a fabricator such as IAP on this board.

Jon

 

[preons]

my vote is put plywood down. I hate to get everyone paranoid but one medium earthquake might be just enough to send that thing tumbling. One good earthquake and we are probably all in trouble. Maybe a good n sturdy in-wall tank will survive. But a couple plywood sides makes it ten times stronger.

 

[marinelife]

I have sides on it now and am still adding the finishing work to it as I get time.


northstaraquatics - thanks I will do that, also what makes you say leave it?

 

[Bainic]

I would put plywood to distribute the weight more evenly on such large and heavy (filled with water) tank. 3/4" would be best.