Size of sump for 90 G ?

[Chin_Lee]

Regal
consider adding overflows to your tank by having some pieces of glass cut at a local glass store. Then just silicone them into place after you've got the holes drilled. Cheap and probably won't cost you more than $40 in glass and labour.
Is your glass tempered at the bottom? Are you planning to drill the side or bottom (if its not tempered)? the rate your bulkheads will drain the water will depend where its located on the tank. This is because if you have it lower in the overflow, it will have higher water head pressure causing it to drain faster. If its higher in the overflow, it will drain slower due to lack of head water pressure.