Need Return Line Advice

[harryggumb]

I'm currently in the process of setting up a 75g saltwater tank with a 20g sump. I'll be running 2-3 power heads, proteins skimmer and a return pump that flows 950 gph. I was wondering what size return line I should use. At first I was thinking ¾" but now I'm not sure if I should go up to 1" or more. Any advice would be appreciated.

[cornishrooster]

I've always heard it's better to go bigger, so 1". Also depending on how many elbows and how far your line has to go you're not going to get 950gph.

[Jasonrusso]

Vertical head loss is the most drastic. How much higher is the return?

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[harryggumb]

Originally Posted by Jasonrusso

Vertical head loss is the most drastic. How much higher is the return?

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The return to the top of the tank is about 4ft

[cgthebeast]

Then you'll lose quite a bit of pressure. Also hard plumb the return, much safer and less likely to blow. I've installed a flow restrictor and check valve on mine because it will drain the tank if it's return is underwater (and of course it will be)

[Jasonrusso]

Read the flow charts. I have 2 expensive Eheim pumps. After 4 feet they are less than half of the zero foot flow rate.

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[PB_Smith]

3/4" will give you a more powerful return stream, and 1" will give a less powerful stream, but both will handle whatever your pump can put out.
I have 3/4" return line that splits into two returns on my Jabeo 1600GPH pump and it works fine, but your pump is ~ 50% the rate of mine, so probably only one return.

[harryggumb]

Thanks for all of the great information. What do I need in order to connect the once to the output in the pump

[54seaweed]

I run a 1" return and a 1 1/2 " overflow I agree with PBSmith that a 3/4" return will give you a better flow , I'm working on down sizing myself ,

[cgthebeast]

I run a 1 1/2 drainand a 3/4 inch return on my 75g. My drain is flexible and I hard piped my return. You'll be looking at male and female threaded bits and pvc glue in order to seal it. My also 90 at two different places and I still have enough flow that it moved substrate

[harryggumb]

It's recommended that I use pvc for the return line as opposed to a flexible tubing correct?

[Fresh2o]

Originally Posted by harryggumb

It's recommended that I use pvc for the return line as opposed to a flexible tubing correct?

I feel the consensus would be "Yes" to this, but this is a good question since canister filters use flexible tubing. I'm thinking that return pumps (can) generate more pressure than canister filter pumps.


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[cgthebeast]

Yup, pvc is the safest way. Keeps from blowing any clamps and such off from pressure

[PB_Smith]

Originally Posted by cgthebeast

Yup, pvc is the safest way. Keeps from blowing any clamps and such off from pressure

LOL...
if there is that much pressure going through the system, it would be a tornado in the tank.

Flexible vinyl tubing is perfectly fine and safe, just make sure to use actual hose clamps on them, not the plastic clip ring clamps.
The only pvc on my set-up is the about1' for the drain and that connects to vinyl tubing, everything else is 1" vinyl hose, about 10' worth and I have had no issues whatsoever.

The benefit of tubing is you can make more "graceful" turns and reduce flow restriction.
If you do use pvc make sure to map it all out first and dry fit the parts to be certain it is how you want. Also be certain to place valves and disconnects at key points to make maintenance easier.

[cgthebeast]

Oh yeah, It was blowing away my substrate from the main high points if flow. The flow value fixed that though.

[PB_Smith]

Ya know one other good option is to use both rigid and flexible pvc. That way you get the added security of the welded joints of pvc and the benefit of being able to route the plumbing however you need to with minimal restriction with the flexible pvc.


Yeah, that is probably the best way to go and is what I will do if I re-plumb my set-up.
the only caveat is that flexible pvc is more expensive.