large acrylic tank on slightly bowed stand

**Brhino** · 01-08-2013, 12:18 AM

This is a repeat of something I mentioned in my journal but I wanted to give it its own thread for increased visibility.

I have a 300 gallon (8'x2'x30") acrylic tank that I build a stand for. Upon placing the empty tank on the stand for the first time I noted that the stand is slightly bowed such that the right and left end of the tank rests on the stand but in the middle there is a gap, approximately 1/4" wide, between tank and stand. Note that the stand is not bowing due to weight. It is solidly built but just not completely flat.

I am wondering what the ramifications of this are and how to deal with it. I am particularly hoping to hear from anyone who has first hand experience with large acrylic tanks, or who has a good understanding on the mechanical forces at play in this situation.

**mrramsey** · 01-08-2013, 03:05 PM

Brhino -

While I do not have any first hand experience with acrylic tanks, my construction / engineering background tells me that you should fully support this as much as possible. I would think at least solid contact every 12" along the seams.

It would be helpful if you link a pic of the current situation for better clarity.

**Cermet** · 01-08-2013, 04:52 PM

I had assumed that you would use the frame supports (by shimming between the vertical supports and the bottom part of the underside of the wood panel supporting the tank base) to counter that bow - that is a serious issue.

**Brhino** · 01-08-2013, 05:09 PM

yup, that would have been a good time, but unfortunately I didn't detect this until I had an actual 8 foot object on top of the stand. In hindsight I should have put the tank on for a test fit immediately after placing the top plywood on, before the glue dried.

I've talked to the same mechanical engineer that helped me design the stand and his recommendation is to place another thin piece of plywood on top of the existing top, and then shim between the two pieces so that the top one is flat and fully supported. That's the best plan I've heard so far.