Originally Posted by 67Elmo
Thanks all for the advice. I have decided to put a 50" long sheet of 3/4" plywood on the top of the stand (plus a sheet of styrofoam over the plywood) which will solve any potential problem. I suspect I "probably" would be okay, but for the peace of mind and the safety of my rapidly growing Koi Anglefish, I'll go the plywood route.
You can do that but you only need it to the edge of the tank. The additional overhang is not adding any strength, and might look "funny".
Generally manufacturers of tanks with trim recommend against any foam under the tank, as it can support the glass pushing up, allowing the edge to settle into the foam, and cause failures. You might check. It is tanks with side glass resting on the bottom glass that need foam. Tanks with side glass resting on the trim (or base) and bottom glass "floating" glued to the sides are not supposed to have foam.
Check with the manufacturer if in doubt, as what seems to be helping (the foam) may be hurting.
But the plywood is definitely a good idea, don't allow the trim to hang off, but you don't need more plywood than right to the edge of the trim unless you just want it.