Coils for GP 3500

I am new to beeping for the elusive nugget and have just bought a GP 3500 (all I could afford), it came with an 11" DD Commander and I bought an 18X12 Coiltec Goldstalker mono coil and a N.F. 16" round mono coil, I would like info on waterproof coils that I could put in some of the little creeks around here in Idaho(USA) that I know might have some little nuggets and maybe some info on other coils that are good for ground that is not considered hot ground. You pro's from down under input would be highly appreciated. Thanks, Les from Idaho

Thanks Jen58; I gather it would probably be a good idea to seal up the coil cord connection with some silicone? I would sure love to put the coil down under a foot to 2 feet of water in this one creek I know has some nuggets to be found. (It's in a designated wilderness area that's closed to metal detecting, but you can ride horses, pan and sluice for gold, go figure!) That is one law I just don't understand. This location is so remote in the back country mountains with a long hike that I doubt I will never see another human being. Quick  Bears and Cougars maybe!!