Return Pump

So it looks like my Iwaki 40RXT is having some issues.  The flow rate out of the pump is maybe a 4th of what it should be. 
I took it out this morning and swapped it with an Iwaki 30RXT.  Looks to have the same flow as the 40 with the return issues.   I tore apart the 40.  Impeller is fine.  Cleaned up the impeller and housing.  Magnet is still strong as ever.  Took me awhile to pry them apart.
Could I have a clog in my plumbing somewhere?  Not sure what else would be killing my return rate.  Anyone able to test the pump for me and see what could be going wrong with it?
Thanks,
Thy

 

If there was a snail in the pump he climbed out while I unscrewed the unions cuz I didnt see him in there but then again I dont think they'd make it down there. Got to go thru two bags of stire glass, carbon, a 100 micron filter pad, and then a sponge from and aqua clear 110 before you'd get to the intake of the pump.

 

Both of my intakes are covered with a small sponge to help with surface skimming. My guess on that is if there was a snail there then I'd see lower water level in the sump but that does stray about normal. I am seeing a larger evap rate when I started seeing problems with the flow rate of return on the 40RXT. She was a bit toasty when I unhooked her this morning as well so I was started to wonder if the pump wasnt over heating or something to that nature.

 

I fear that may be the problem. So now I am looking into getting a new external pump around 1500 GPH. Anyone got one really really cheap? IE under $100...