I have found my ace 350 to be very accurate in the sand and run mine at full sensitivity. That being said,I am land locked with no saltwater to contend with. I find the beaches and sand volleyball courts most receptive to full sensitivity hunting, but there isn't any random junk washing up on the beach at the local reservoir and the volleyball courts seem pretty clean . There also isn't a ton of treasure washing up on the beach either. 4 inches in depth and less I feel like I can trust the target I'd and depth most of the time. I am also hunting fresh deposited items in play grounds and nice green grass parks most of the time anyway. I have recently been hunting an old school site where the conditions are different from the average tot lot and park. In the hopes of finding some silver , I am running zero mode and max sensitivity. I have been digging anything above iron and finding coins in the 2-4 inch range that aren't as obvious as they ring up in coin mode in a tot lot. The dirt is all baked out in the late summer heat and the signals seem to jumping around a little more. I can't really say I have found a real interpretation or technique for of it all , but I am digging coins.
The one thing I have noticed when running in zero mode, is that it's easier to pick the coins out of the trash. That doesn't make sense right ? A pull tab , foil or can slaw seems to overwhelm things and beep somewhat randomly when running in coin mode. seems to have more delay in signal processing and it makes you think you have unrepeatable junk signal when the delay in the discrimination is causing the detector to miss the good target sometimes. I also tend to slow down my swings to give myself a chance to catch the tones I am looking for when I am in zero mode. I have been able to zero in on potential good targets crowded by trash signals in zero mode. I don't know, probably having better luck with it cause I am slowing down when I hear all the targets beeping at me. Any way , love my 350 and feel its a good upper entry to lower mid machine.