40B Return Pump Replacement Help

[aaron186]

I have a 40B with a 20gal sump. My return line is 1/2 inch PVC that has one 90 elbow and three 45 degrees elbows and then a short run of soft tubing to the pump which is about another 45 degrees bend to the tubing. It is about 1/2 foot horizontal and 3 foot vertical run.



I previously had a Jebao DCT 4000 on the tank and had good flow through the return. True to the reviews it died on me in about 6 months. I purchased a sicce syncra 2.0 a few weeks ago. The pump doesnt seem to be strong enough though I love how quiet it is.



The Sicce Syncra 3.0 is a bit more than I want to spend but I might pull the trigger, especially if I can get amazon to take the 2.0 back. I am also not sure if this will be strong enough.



Can someone recommend a return pump for me? I would like to keep it around $60-90 if possible



Thanks,

Aaron

 

[mcarroll]

I would upgrade that return line to no less than 3/4" PVC. You'll be needlessly throttling the heck out of any pump you put on there at 1/2".

The 2.0 will work great with the proper plumbing – you might even be able to downgrade to a smaller model.

According to this (which is accurate) the 2.0 is overkill by double – a Syncra 1.0 would do the trick....a 1.5 would be oversized:
Sicce Syncra Silent 1.0 Multifunction Aquarium Pump (251 GPH) (marine depot)

 

[mcarroll]

40 gallons * 4 = 160GPH is all you need, BTW, and should be more than adequate. Oversizing past 200GPH isn't really warranted for any reason in most scenarios....just wastes money on the pump and uses too much power vs a right-sized pump.

The importance of right-sizing is why Sicce and Mag and the other majors have so many models of pump. If you size it right, they are extremely efficient....on par with that DC pump you had that gave you a bad experience.

 

[aaron186]

My tank is already filled and drilled so upgrading PVC isn't an option

 

[mcarroll]

That's very unfortunate as 1/2" really is crushingly restrictive.

Here's a comparison between 1/2", 3/4" and 1".

From http://www.freecalc.com/fricfram.htm – accounting for the fittings your mentioned, allowing 4' of PVC, and one entrance and one exit.

Liquid Friction Pressure Loss
Line Number: 1/2" PVC - 200GPH Pressure Loss (psi): 0.36 Head Loss (ft): 0.8
Line Number: 3/4" PVC - 200GPH Pressure Loss (psi): 0.11 Head Loss (ft): 0.2
Line Number: 1" PVC - 200GPH Pressure Loss (psi): 0.04 Head Loss (ft): 0.1

(that "head loss" number is what you'd add on to the 3+ feet of vertical PVC you mentioned...so 1/2" PVC adds almost a whole extra foot.)

1/2" PVC is....

More than 300% more restriction vs 3/4".
More than 900% more restrictive vs 1".
​

This is why your current pump is under-performing.

Depending how much this matters to you, you might consider switching to a Mag pump - they're designed on 1/2" threaded inlets and outlets instead of 1". Might work better.

A MODEL 2 MAGNETIC DRIVE PUMP 250GPH or MODEL 3 MAGNETIC DRIVE PUMP 350GPH would do the trick.