Starting to set up my 134? That's what the calculators say it is in gallons. I started to build the stand frame the other day. Tanks got 3 returns and 2 overflows. The two overflow holes are 1 1/2 and 1 that's the size hole drilled. So that gives me a 1" and a 3/4" drain I believe. Do you think that's enough? It has 3 1 inch returns. I have a mag 18. Should I drill another overflow hole?