The PSK 2500 is a darn good and very reliable pump if you modify it correctly and don't try and push the pump beyond it's limits.
I would say this pump has more aftermarket accessories than any other pump before it, trying to get just a little more air to skim a bigger tank or fill up a bigger skimmer body has destroyed the reputation of the pump to a large degree.
The white pinwheel we use is actually from Jon Warner's K2 skimmer (original), we bought them a year ago when he changed to the Red Demon and found that it had the right balance of weight, number of pins, size of pins and diameter to accomplish our goal: To create a RELIABLE Sicce pump without the LPH bragging rights. 800LPH is what it pulls and it does so day in and out without start up issues, we matched the skimmer body (7.5" base) and neck (3.75") to the pumps capabilities rather than trying to beef up the pump to put on a larger body skimmer (like the K2). More air, means bigger pins, larger diameter wheel, etc which pushes the pump past it's safe trouble free operating range. AVAST's core philosophy is to provide reasonably priced and reliable equipment, not win SCFH trophies
The only modification done to the volute is to machine out the water intake on the cover, install the air intake and to add the right size reducer to tune the air to the 800LPH mark.
