When I see a hunter stating they want to beach hunt (especially if it's a salt water beach), the first thing I say is, get a waterproof unit.
Stating that, your E-Trac can hunt any beach, fresh or salt, BUT IT'S NOT WATERPROOF !!! When hunting salt water beaches, with the salt air, water and harsh environment on electronics, it is almost imperative that one have a water proof unit or a unit where it can be heavily protected. It is very hard to fully protect an E-Trac from the salt beach environment. Also, even if the unit is heavily protected, you can't totally rinse off the unit with fresh water, as you can with a unit that is water proof.
If I were you and were going to use the E-Trac on the beach, the dry and wet sand is all I would hunt. I would NOT take a chance in shallow water. I took my E-Trac on a salt water beach and hunted the wet sand and suds, The unit worked great and I found 2 pieces of gold. But I got swamped by a wave and the water splashed up pretty good and almost got the detector. No more of that. It is now relegated to strictly land hunting as I have several waterproof units and units better served for that type of hunting than risking trashing my E-Trac.
I say save up and get a good water proof unit. You will not regret it. What you will regret is if the E-Trac gets a bath it should not be getting.