# pump for 20 gallon sump



## kevin3020 (Jun 7, 2008)

I am making a 20 gallon sump for a 75 gallon tank and i was wondering what the best submersible pump is to use. Here is a diagram of the sump.


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## KaiserSousay (Nov 2, 2008)

Gonna need a bit more info. Kevin.
What are you using to get water to the sump?
Need to know the in before helping on the out.


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## kevin3020 (Jun 7, 2008)

Sorry, I'm going to use 1.5 inch pvc for the intake and a 6x6x6 overflow. Anything else you need to know?


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## KaiserSousay (Nov 2, 2008)

Maximum Gravitational Vertical Flow - This is what we look for when sizing drains or DIY overflows. The flow under the power of gravity reaches a maximum in the same way an object reaches Terminal Velocity as it falls through the air. The gravitational force is countered by the waters viscosity (resistance to flow) and the frictional resistance of the pipe. The viscosity creates a minimum vertical length to acheive the maximum flow. If the vertical pipe length is less than the minimum, the flow rate will be somewhat less than the pipes maximum potential.
size _GPM __GPH 
1/2 = 2.50 = 150 
3/4 = 5.63 = 337.5
1.0 = 10.0 = 600
1.25=15.6 = 937.5
1.5 = 22.5 = 1350
2.0 = 40.0 = 2400
Above from MFK DIY sticky, your max flow should work out in the 1000-1250 gph range, just a guess.
For a pump choice, I would look to a 1350+ capable pump. Not anything smaller.
:-? But, wait a sec., didn`t you just say the flow would be, like 1250 max, says you.
:thumb: Right you are, says I..but I would always want a pump that has a "cushion" over and above my actual need.
You can always redirect any excess flow back into the sump, but once a pump has maxed it`s flow out..you be done. I tried to "cheap" out on a pump, only once. The few extra dollars spent on a bigger pump, would have put a number of headaches to rest.
HTH, and good luck.
Post some pics when you got it running.


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## mel_cp6 (Feb 3, 2009)

i see some problems with your sump design.
1. make 3rd divider 1/2 - 1" lower.
2. make last divider around 6-8"
depending on your overflow you may have a high risk of flood with
that design. also you may want to look into 20long if you dont already have 
the tank.
you need to know (calculate) how much your overflow will drain from the tank during
power outage and make sure your sump return chamber area can handle this.


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## fox (Jun 11, 2009)

I just made W/ D sump/ fuge out of a 20 Gal tank for a 65Gal tank. Fishless cycling it now.

You might consider relocating the refugium from the center to one of the ends. The flow thru the fuge should be less than the the total flow thru the sump. You do not want 5 - 10X turnover thru the fuge.

I Tee'd off the drain/ return line and let some of the "dirty" unfiltered water flow into the fuge, shooting for a 1-3X flow which spills into the pump chamber and let the rest of the return continue to the W/ D filter area which empties into the pump chamber.


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## kevin3020 (Jun 7, 2008)

Here is a new and improved design.


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