I'm going to start with the cheap 75g while I wait..

[ReefMasterRed]

I've had an empty 75 gallon and stand I got from petsmart 3 months ago (impulse buy) it was 35% off, I found a blemish, very minute but still present in the stands base board on the back corner I haggled with the manager and walked out with stand tank and cheap led light for 225$. As soon as I got home and set it in the intended room, I knew, sat to low, wasn't big enough, and wasn't rimless. 3 months go by and I'm ready to get back into reefing after 10 years! I drill stone and glass all the time as part of my occupation, and am very familiar with reefing from 10 years past. I'm looking for suggestions on the best overflow (position, and size) location of return lock lines nozels and quantity (for optimum flow) and equipment to fit in a 30 gallon diy sump which will fit perfectly in the stand. The creation of the sump will be determined by the input here and the build will be highly documented while I await the sale of a reefer 750xxl for my dream display tank, I can't wait any longer to get the cycle started. In the end game this 75 will be either a quarantine for small sharks or a frag tank. I appreciate all positive input and can't wait to get this glass box wet.

 

[pluikens]

I like a high flow rate through my displays so I shoot for 10x. If I were building a 75 gallon as a display, I would use a 16" Shadow Overflow. Ideally, I would get an overflow from Modular Marine but their store has been down for a couple months now and I don't know when it will be coming back up. There are other options like the Eshopps Eclipse ( medium would be OK but I like two bulkheads through the glass for safety) but for the slight price difference between Large Eclipse and the 16" Shadow, I'd be going with the Shadow. I have a 90 gallon right now as a grow-out tank with a corner overflow in one back corner and the return on the opposite side on the back wall. I like how this gets most of the surface water to move from right to left at the top of the tank. This is similar to my 40-gallon display that I drilled with the overflow on the back wall on one side and the return on the opposite side. If I were to drill and install a Shadow, I'd put it on the back wall (assuming it's not a peninsula style install) with the return opposite like the 40-gallon I've done. I like to drill holes of just one size so I drill 1" holes for all of my smaller tanks (90 -gallon and under). I then step the 1" return bulkhead down to 3/4" and install a short piece of Loc-Line followed by a @Vivid Creative Aquatics RFG nozzle. Hope this helps!