Return nozzle placement

djmincer · 2026-10-14T04:47:32-0400

Hello! I have a 125g tank. My hang on back overflow box Eshopps 1100 has to be on the right end of the back because I have a gate valve on the drain line that I have to be able to access easily in a tight spot. My sump is below it in the stand. I am going to have two return lines from the sump — one will be direct and the second will flow through a UV sterilizer. Where should I locate the two return nozzles along the top on the back of the tank? If I put one on the left end of the back and the second on the right, the one on the right I think would need to be between the hang on back overflow box and the right end of the tank, correct?

Piotrek · 2026-10-14T05:36:25-0400

A picture or a drawing of what you are planning would help.
For the UV return - doesn't matter much where you put. Best as far away from the overflow box as you can, but the flow trough it has to be so low, that it's maybe better to return it to the sump for simplified piping.
For the main return, I would choose any of the 2 -
1. next to the overflow, pointed at the surface,
2. on the other side, pointed slightly towards the bottom across the tank.
Personally I favor option 1 for simplicity.
If you would consider 2 equally efficient returns (with UV being the 3rd), the on the opposite sides of tank, both pointing at the surface.