Return Pump Sizing

[DrRob]

Simple question, which I'm sure will spark a lot of debate.

If someone gave you a 36"x24"x18" tank, with a sump, all drilled nicely, what size return pump would you put on it?

I know the principles of sump tanks, but have never actually set the pumps up on one.

Stocking will be an extension of my current community.

 

[DrRob]

OK, so no debate at all.

Time for a more specific question.

A 50 gallon tank, with a sump that can handle 20 (and therefore won't, otherwise it would overflow), with about 1.5 metres from the bottom of the sump to the top of the return pipe.

Would people go for 2 of these

http/www.charterhouse-aquatics.co.uk/catalog/eheim-compact-1000-pump-1501000-ltrhr-p-344.html

with the advantages of redundancy if a pump fails/clogs and ease of supplying return systems like CO2 reactors with lower flow water, but the risk of unacceptable flow loss with the head involved...

or 1 of these

http/www.charterhouse-aquatics.co.uk/catalog/eheim-compact-2000-pump-10002000-ltrhr-p-1055.html

with the better power and head stats, but a higher overall price and no redundancy?

Or something completely different.

I'll probably be throwing in one of these to keep the plants moving as well.

http/www.charterhouse-aquatics.co.uk/catalog/hydor-koralia-nano-evolution-900-circulation-pump-p-3471.html

 

[daz4321]

The decision on the maximum flow through the sump you can have will be dictated by the size of the drain lines and their design.

 

[DrRob]

Ahhh, the drain is a 1 inch open syphon that can be throttled back to allow the second drain which is a 1.5 inch durso to run a little, and hopefully relatively quietly. Should mean that they can handle pretty much anything either option could throw at them.

 

[daz4321]

well approx you are looking at about 50% loss in flow at 1.5 m on the compact+ series of pumps so the 2000 would pump about 1000l of water at that head height. hope that helps the decision.

 

[DrRob]

It does help thanks, it would mean about 4 times flow, which is fine for the sump flow with powerheads to keep the circulation for the plants.