Bill,
I have a Vaquero and have used it in a wide range of soil conditions. There are those that complain about not being able to get a good ground balance under certain conditions. It is true that under some ground conditions you will not be able to get a PERFECT ground balance even with reduced sensitivity. The 3 1/2 turn ground balance control just does not have enough resolution to get it perfect. My Gold Bug 2 has a course and a fine adjustment and the fine is a 10 turn control. However, you can always get it close enough to still have excellent performance. Remember, if you can't get it perfect always set it so the threshold get a little louder as the coil approaches the ground. This will insure that you will be able to find the smaller weaker targets.
I balance my Vaquero this way on the beach. I have to run the sensitivity around 8 and since salt water is conductive like real targets I have to run the discrimination right under iron to eliminate the false beeps or keep them to a minimum.
Each detector is slightly different so you might have to tweak this settings a little differently on your detector. However, if set up right it will do a very respectable job on salt water beaches. I think better than most VLF detectors.
Good Luck with your new Vaquero It is one of the best on the market and will fill your treasure chest with great finds if you take the time to really use and learn what it is telling you.
God Bless,
Smitty II