2200gphis 36.6 gpm . and actually less than that because you have added resistance with tubing and gravity. That is why do need more drop per foot. You are also now having to classify your material pre sluicing. and feed slower. With that pump you can't really run to quick. Its a great set up if you lose riffles, run expanded over carpet only. If your material is classified to a size that is smaller than your riffle height. You are actually working against your self. That's why stuff is building up in front of your riffles. You are running a closed circuit system, check your tailings. If you find more gold in your tailings than you recovered you have a problem. If you do have clay and sand building up on the front of your riffles, it could keep fine gold high up in your material. As it comes through and may ride out. I doubt it though, she looks to be running well enough. I just think you would benefit from more water volume you could run your sluice flatter and have the abilty to turn the flow up when and if you wanted to run more material faster. For cons it is a good unit.
