Drain and return line sizes?

[mark.wittig]

Hi, all. New to this hobby. I used to be into freshwater and, now that I have settled down and stopped moving (retired from Army), I am getting into saltwater. I have a 180gal setup that is just about ready. Got my sump, pumps, refugium (in sump), skimmer (in sump), lights, APEX, RO/DI, reservoir, etc. all ready to go. I plan on starting out FOWLR and then moving to a mixed tank slowly as I learn more about the hobby. I will start by adding soft corals and then adding hard corals depending on experience along the way.

My display tank is an Oceanic with 2 overflow boxes. One in each corner. Each overflow has 1 1"bulkhead and 1 3/4" bulkhead. I have a 40 breeder sump in the tank stand. I have 1 1/4" durso standpipes for the 1" bulkheads. And I have 3/4" loc-line for the returns coming out of the overflow boxes.

I have a MAG24 that will be external to help with heat management on the return line. The MAG has 1" input and output. I have a branch on the return line with gate valve to regulate flow by dumping some back into sump if needed. I will also have unions so I expect the flow back to display tank to be around 1400 - 1200 gph. I also have 2 Tunze 6100s and 2 Koralia 1400s in the display tank for flow.

I have 2 questions before I complete plumbing:

1) Should I go with 1 1/4" schedule 40 drain lines of 1"? I would use 1" schedule 20 as adapter coming from bulkhead to keep 1" diameter and the go up to 1 1/4" schedule 40 for the return line to sump.

2) Should I go with 1" schedule 40 return lines or 3/4"? I would use 1" from pump all the way up to the 3/4" bulkhead and then reduce to 3/4" schedule 20 for connection to bulkhead. Inside overflow box, schedule 20 from bulkhead to 1" schedule 40 with 90 degree elbow reduced to 3/4" to 3/4" loc-line.

Thoughts and feedback?

Thanks!

[Sisterlimonpot]

First off, Thank you for your 20+ years of service in the Army.

As for the drain, it all depends on how much flow you want to go through your sump/fuge. A common school of thought is to allow only enough water to flow through your sump/fuge that your skimmer can cycle through. that way the skimmer is getting the majority of waste out before the water is returned into the display. But there could be other factors that determine a faster flow rate through your sump/fuge.

I have a 125 running a mag 18 with 2 overflows that are 1" sch20. With the mag flowing at full capacity at 8' of head the 1" drains are fine for that much flow, I have ball valves on the returns to restrict the amount of flow back into the tank, so the movement through my fuge is fairly slow (if I guessed it was 200-300GPH) tho 1" drains are plenty big enough.

As for the returns I have 1" coming from the mag 18 and and when it goes through the bulk head it is reduced to 3/4 just to accommodate the loc-line.

HTH

[mark.wittig]

Sisterlimonpot,

Thanks for the feedback! I am expecting 600 - 700 gph per drain. Appreciate the thanks for service. Just thought I would mention why I settled down so folks don't think I can't hold down a job! LOL.