[wildreef]

Most will sit the skimmer inside the sump "depending on the room availible"
but you can pull the water for the skimmer from the sump and return the same back to sump.
general rule of thumb is 10X turn over rate of full water cpacity in one hour(60 mins)
Of course, more the better.
I should think walsh , a good 1000 to 1200 gph pump would do just fine.
But keep in mind of pumps, the more line you have to lay for it to return to the tank , it will lose head pressure (meaning it loses it's volume over time/and pressure )
A pump that puts out 1000 gph at the head may only put out say 800 if a person adds 6 feet of line to the pump.
best to check out all the pumps availible, some have higher pressure, some have higher volumes.


So lets say for instance you have 75 gal. tank and a 30 gal. sump =105 total gallons you want to acomplish at least
a turn over rate of 10 times an hour of total water volume.
So> take any gph pump say a 900 gph. and divide by 105(water volume)= is only 8.5 times of total water turn over .
lets bump the pump to atleast a 1200 gph. which would give you a total of 11.4 of turn over per hour
Now that's acceptable.

( p.s check my math it's 3am in the morning and the wife has insisted i take a sleeping pill, LOL )