closed loop question


Alleged Lounge Moron
My 2nd newbie question this evening.

Answer is prob plain & simple, but I have not seen a diagram/picture in my research.

Given the large flow thru a closed loop, How do you keep from having everything in the tank pulled into the pump intake, what is the supply side protection?
Hope that makes sense.

Getting ready to drill for sump & CL, still trying to figure things out

Thank you.
I have an over the top closed loop system made from a 2" black pvc pipe. I drilled 200 3/16" holes in it to keep the critters out of it. If you're drilling the tank for a closed loop you can buy filters to go in the inside of your tank to use for screens. Check fosterand smith or marine depot.