I have a couple of things to tell you.
NO ! NEVER lift your coil up high enough to let the salt water drain back down the rod and into the machine. That is a big no no with the E trac with the hollow coil rod.
NO 2. On black MINERALIZED sand I will block out (discriminate out) the top of the screen one or two rows until the falseinggoes away. What I mean by this is; if you have an open screen you will get lots of false hits on the black sand, it being able to look like a good hit and sound like a hit. Usually I only have to go down two rows and it makes a big diff. If your in an area where you might find a silver dollar then bring one and test it after you make changes. You may want to open back up an area just a bit. Experiment a bit for your area. I've been pretty successful that way and its much quitter. I hunt with a pretty open screen other than that , except I will still discrim out the iron part of the screen. The E trac will find gold but usually large size gold. I found a few small gold items but they are very VERY difficult with the E trac. I still experiment with small gold every hunt before I go to beach's and try to find a setting I think will help. ( I'm looking for a certain lost ring 8 years now).
No3. Get Andys book and take a hard look at the beach hunting recommendations. You can modify from there as you figure out your kind of finds there.
No4. I cant tell you enough the benefits of wearing a good pair of headphones at a beach especially on the black sand.
Im sure there are experts out there far better than I at the black sand. Im just sharing some things ive learned along the way.
Good luck,
be sure to post your finds<
Shov