sump return area size

[beanoil]

I'm using a 20L to build a sump for a 58RR. I've been following a lot of the sump threads and the comment is always made to be sure the return area is large enough to allow for evaporation. I understand the importance but I'm not sure what "large enough" translates to. Is there an equation out there to figure out the proper size, i.e. how tall and where should that last baffle be? Thanks.

Grant

 

[BeanAnimal]

Tall enough to prevent the pump from sucking air and short enough to allow a safe running height. Remember the sump has to fit all of the extra tank and plumbing water when there is a power outage.

What is big enough? Figure anywhere from 1 to 5 gallons a day evap (depending on your setup and environment). You can use the volume of the space to determine how far the elvel will drop for any given amount of evap.

A gallon is 231 cubic inches.


Lets put it this way, if your return comparment is 12" wide and 12" long and your minimum pump running depth (before it sucks air) is 6" deep, and your max sump water level is 9" (to leave room for overflow)....

This means that your total evaporation area is 12 x 12 x 3 or 1.87 gallons. I hope this gets you started.