There is a myth amongst a lot of people that PI's aren't good for fresh water. Nothing could be further from the truth. When used properly and at the right locations, they work well, either in fresh water or salt water locations. I only hunt fresh water lakes where I live.....below are my finds from that first year. My buddy who also bought a PI experienced similar results. From my results....VLF detectors miss a lot of rings/coins.
Excal 1000, Excal II, Sovereign GT, CZ-20, Tiger Shark, Tejon, GTI 1500, Surfmaster Pulse, CZ6a, DFX, AT PRO, Fisher 1235, Surf PI Pro, 1280-X, many more because I enjoy learning them. New Garrett Ca
I have tried to use my Sand Shark and Surf PI Pro in a lot of freshwater lakes but tiny pieces of hair pins can last decades in fresh water. My time was not well spent. However if you can't hear it, you can't dig it.
I used my Sea Hunter II in a lake while using scuba and I was digging up bird shot, drove me nuts. I guess I could have turned the discrim up but I hate having to do that, don't want to loose the good targets. These are very sensitive machines but for freashwater swimming holes I perfer the AT Pro.
Salt water I perfer the Sea Hunter.
ZDD