I've had the same experience. re. lots of deep Wheaties, NO silver! It's possible, though not likely, that I haven't been going over silver (see below). And of the 4 sites I'm going to mention (now fairly trash-free), I've detected them all within the past few months (after many hours before that) with the CTX. Pulled out dozens of silver coins at each over the past 2-3 years. Never saw another detectorist or signs of digging (though that's not foolproof re. cherry-picking) I've sent essentially the following to Minelab, and am awaiting their reply.
In giving my new Equinox 800 a test run, an unusual retrieval pattern has developed. I took it to 4 sites (2 schools, 2 parks) that I’ve ‘hunted out’- pulled dozens of silver coins from each in the past, and these past 3 weeks went over the same ground with my new Equinox, where the acre or less ‘hot spots’ were. The detector progression was: Explorer SE with 15-inch ‘butterfly’ coil, CTX 3030 (stock coil), and the 800.
Soil conditions varied from fairly dry to very moist. Equinox settings were: Park2 – Fe Bias 0, Recovery speed – 4-5, Multi-frequency, 5 tones. I set up the highest tone for copper Lincoln cents and above – 22-40, and dug only those signals for now. (Somehow one Indian cent snuck in there.)
Otherwise – I’ve retrieved 43 Wheat cents, more than half of which were at 6-9 inches deep (nice!). Most of the latter gave scratchy signals, which from experience I’ve long ago learned to dig. The huge surprise – not a single silver coin has come up! Any way you can help me explain this?
For my 20-year career detecting (I detect mostly public, oft-hunted ground), the ratio of Wheat cents to silver coins has been ~ 6-7 to 1. This has been repeatable on an annual basis. But 43 to zip? I gotta think that there's still some silver left, with the Equinox NOT outperforming the CTX for silver.
I can think of only two explanations for my recent experience: the 2 older Minelabs (especially the CTX) were HOT on silver coins and less so for Wheaties, leaving some of the latter behind. The other thought is, that the Equinox is HOT on copper coins, and much less so for silver coins. Perhaps someone at Minelab who knows more about detector performance and internal makeup (design engineers?), can comment on these results and my 2 possible explanations. Thanks. {End of note to Minelab.}
At other sites than these where the trash is also 'minimum', I'd like to feel confident in either the Equinox or the CTX for silver (I'm a silver junky!). [Since I wrote Minelab - spot I've been over many times - I got perhaps my deepest coin ever (with the 'nox) - a large brass token at a real 11+ inches.] Impressive, but I didn't buy the 'nox to dig copper coins. Right now, the Equinox has its place, but I'm not selling my CTX! (I think the above is the best test comparison I can make, other than having both machines running and comparing them live, for too many hours.)