Dumb AGA Tank Question
 

I know my 90 gallon Mega Flow tank I have has a 1" bulkhead for the drain to the sump and a 3/4 bulkhead for the return. Can I put a 1" bulkhead in that factory drilled return hole to add more flow into the tank or am I stuck with the 3/4 size? I just don't want to tear it apart to find out and I cannot find any literature on the drill hole sizes. Any help with someone who had tired to make it fit would save me a great deal of time.
Thanks.

how big is the hole cut in the glass for the 3/4" bulkhead?

hmm why do you want this anyway? you have to remember a 1" hole drain from your tank will only allow (X) GPH water through it. if you put a pump thats too big on the return to the tank you may overflow due to the drain not being able to keep up.

1" bulkhead = 1.75". 3/4" bulkhead = 1.5"

i have had this same problem. i went from a mag 7 to a mag 9.5. the mag 9 said that i needed a 1 1/2 returni.d. pipe for max flow. im using a 3/4 bulkhead (which is the max for the hole given) and it works out great. just go with the 3/4 bulkhead and on each side of the bulkhead use a adapter or a 3/4 to 1in. bushing with a coupling. that little of a reduction will not affect much if anything.

IMO using the return as the major source of flow in the tank is a bad idea. Running 600 gph through the stock return on a 90 is plenty. The rest of the flow should be made up with power heads or a closed loop.