Do you use the sponge prefilter on your internal sump pump?

In my sump, I have a sponge filter just in front of the pump in the water path to my return pump. All water going to the pump must pass through this filter This one seems to catch bits of macro algae returning from the fuge as well as other “mudd”.

Also I run a course sponge pre filter on the overflow from the tank along with a fine filter in the sump on the overflow outlet. All (3) of these get cleaned every weekend.

Before installing the fine filter on the overflow outlet, I would have to throttle the discharge of the 800 gph pump, (to decrease flow rate) so that it would run a week with out sucking a bit of air (because all water flowing to the pump must pass through the sponge filter, the water level around the pump would get low enough that a vortex forms and the pump begins blasting bubbles into the tank). With the extra filter, I have gone 8 days between maintenance activities with out any air issues.

 

In a sump I'd just hang a specimen cup that has been drilled in the bottom and add my carbon and or Phosguard and floss when needed and I let the outlet from skimmer pass through that But if thats not a workable thing for you you can put a tee and a control valve and then pass the drain water from tank through it that away. Gravity always suck and less pump pressure is better and less chances for a spill over And I drill a couple of 1/4 holes just below the flood rim of the specimen cup so it will spill over into the sump when its in need of changing or service. As for a per filter if I used them as i once did I just set the sponge cylinders on top of my overflows .
As for a sponge on a pumps inlet thats never a good idea when its slows and restricts the water to the impeller you will get cavatation from the impeller and that will cause micro bubbles and also kill the pump sooner and cause the coils to heat up. Thats why many lost their old RIO they became restricted in the screens from dirt and Ca and carbonate hardness build you and they over heated. Even on a real high dollar commercial pump to restrict the inlet voids the warranty ..