Bob,
Not all tanks that have been cut for slots in the back have failed. Yours are widely spaced and you seem to have put quite a bit of attention into mitigating these risks. IIRC I haven't read of anyone cutting individual slots in the rear of a tank, all the failures were one wide slot.
Level the stand in the garage or in the basement (near a floor drain!) and test fill it for a couple weeks. I don't have any links handy, but the failures I mentioned were posted within another thread (I think one of the very first threads on the topic).
I clamp glass behind when I drill for bulkheads and it works great (didn't really need it with my slots).
Dan
|