External overflow and return placement questions

[BriDroid]

I’m slowly starting to build my bigger tank. I’ve picked up a Marineland 40 breeder, an Eshopps Prodigy M and a VarioS 2 return pump. I also have a Fiji-20 sump, a Bubble Magus Curve 3 Extreme and an Icecap 2K gyre. It’s going to be my first time drilling glass too!

My question is where should I place the overflow and return? The overflow on the left back and the return bulkhead on the right back? My other option would be the overflow centered and a bulkhead return on each side? I’m leaning towards the overflow on the left and the return on the right. If that’s the case, would you put the gyre on the overflow side at the top or on the return side at the top pushing water towards the return (I’m thinking this is the correct way).

I also have two Nero 3’s that I can use in a pinch if the Gyre leaves dead spots from the rocks. I’m really, really trying to go slow and plan this out!

Final question, how far below the surface should the return bulkhead be?

 

[mfinn]

The last tank I used a Eshopps overflow kit on I put it on the left side and a single run on the opposite side.
My kit was the large. One thing I found out was the pattern they had for the large and the placement they said to use put the overflow a tad low, so the water level was below the tank trim. Had to do a diy fix on the teeth of the inside box to get the water level higher.

 

[Idech]

My other option would be the overflow centered and a bulkhead return on each side?

That’s what I have but it’s my first tank with a sump. I had it custom built. I like it and I don’t regret it. My other choice would have been an overflow/return on each side.

 

[mfinn]

I would put the return bulkhead far enough down so drilling doesn't run a crack to the edge of the glass. I'm not an expert, but with 2" or so of glass above it should be fine.
Then on the inside use enough loc-line so you can turn the nozzle in any direction you need and to be able to raise it high enough to create a siphon break when the pump is shut off or power goes out.
If you didn't want to drill this one, a over the top return isn't uncommon.

 

[UncommonSense]

There’s also the option for a short side pane overflow, in the peninsula style! (Particularly if using a light canopy, to hide over the rim return plumbing discharging on the opposite side of the tank!)

The ASTM (C1048) standard for tempered glass holes (what is usually followed for annealed glass) is that a hole must be placed at least 1.5x glass thickness from any pane edge, and 6.5x glass thickness from any pane corner! (For glass <19mm [3/4in] thick)

— 40B is 6mm glass, so 9mm (~3/8”) from glass edges, or 39mm (~1.5in) from any corner!

 

[BriDroid]

There’s also the option for a short side pane overflow, in the peninsula style! (Particularly if using a light canopy, to hide over the rim return plumbing discharging on the opposite side of the tank!)

The ASTM (C1048) standard for tempered glass holes (what is usually followed for annealed glass) is that a hole must be placed at least 1.5x glass thickness from any pane edge, and 6.5x glass thickness from any pane corner! (For glass <19mm [3/4in] thick)

— 40B is 6mm glass, so 9mm (~3/8”) from glass edges, or 39mm (~1.5in) from any corner!

Thank you! That’s great info!