1 vs 2 Return Lines for Tank

Marquiseo

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Are there any issue/downfalls with have 1 return vs have 2?
 
It decreases the pressure of the return flow.
My 55 has a 10x turnover @ about 700 gph. From a single nozzle it will blow the sand outta the tank.
I have a single return now with a locline split. Its now the primary flow(or current) as it still has a lot of pressure behind it. I use the powerheads to beat up that primary flow and create turbulence.

If you have a lower return rate(or multiple returns) youll have lower pressure out of the nozzle and can just use the powerheads for turb and flow.

My .02
 
Thanks for replying. I pretty much just want 1 return and was just making sure there wasn't anything I missed.
 
No sweat. Its actually a hard question to research.
 
Lower pressure equates to higher flow though since you are reducing the velocity. The less headloss the higher the gpm.
Id assume when you see larger tanks with multiple returns then it because @ a higher gph for turnover you need to lessen the pressure by using multiple return points.
@AZDesertRat
Any clue as to why so many recommend to not use return pressure as in tank flow? that baffled be as my sand blew out of the tank. I mean how could I not? Is that just an old reefers tale?
I have since ignored that advice an myself and my tank are both happier for it.
 
I have always included the sump return in my turnover calculations. I try to limit the return flow to around 5x my display volume though. This gives the in-sump skimmer more time to work and eliminates microbubbles returning to the display due to high velocities in the sump. Even with baffles I prefer lower flow in the sump and make up the bulk of the display turnover with WP controllable wavemakers.
 
Thanks!!
My turnover is too high from the sump return, I know now. (at the 10x "recomended")
But it seems really happy still.

(By recommended I mean pretty much any calculator I found for sump return gph. Oy.)
 
A lot depends on your sump volume and layout too. If you have a small sump compared to your display volume the velocity through the sump would be tremendous and not efficient where a large sump volume and long versus tall would give you more contact time for the skimmer and lower velocity.
In my case I have a 100g display and a 30g long sump that runs about 20 gallons in it. At 5x the display volume or 500 gph I would have about 25 sump turnovers per hour or about one turnover every 2 minutes+/-. If that was a smaller sump the velocity would be much higher and microbubbles could be a big problem. I say the bigger the sump the better and keep the turnover managable or close to what your protein skimmer can process.
 

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