Not all beaches are as bad as discussed in forums. I started hunting beaches with another AD member, SeaBeeRon, several years ago on one of the worst beaches in the country...Santa Cruz, Ca. That beach has so much black sand that you can literally see it in the run-off groves.
Even that beach is huntable with an inexpensive machine...albeit much easier with the more sophisticated machines. Here are just a few comments that might make life on the beach more comfortable and rewarding... Thanx for the input on beach looting, a DD coil (recently purchased) will help me to find goodies now HH ....
1. On every beach, there is a towel line where most beach bums put their towels down. The line will slightly move as the tides vary, but it is a very good place to begin your hunt before the next high tide.
2. When the tide makes a high-to-low cycle, many dropped goodies around the towel line are swept out. Some are deep enough in the sand beforehand to remain, but the tide gets many, if not the majority, of them.
3. Needless to say, a water-proof detector is invaluable at a beach. Wading in water while detecting is an art in itself, but one that is easily learned with the right equipment. Target recovery in the water is difficult, but with a few techniques and the right scoop (long-handled and big are two major requirements) can handle even the most difficult situation.
4. Nails and hair-pins!!! OMG, they are the bane of everyone who is seriously detecting on the beach. Nails are more prevalent on beaches that allow bonfires. Hair-pins are used for everything...obviously hair control, but as bookmarks, etc. If your detector has the ability to mask iron...do it. There aren't many (if any) good iron targets on a beach. (We won't even mention bottle caps.

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5. Speaking of discrimination...If your detector has a discrimination gain control, turn it down (less gain). You simply don't need a large amount of disc gain to identify targets on a beach. Tip: If your detector beeps when you accidently touch the sand with your coil...your disc sensitivity is too high.
6. While we're on the subject of discrimination, let's talk about detectors. Discriminating machines such as the Minelab Soverign are very good on a beach because they have very sensitive controls that can filter out false signals from the sand and provide excellent target identification. The best discriminating machine I've ever used on a beach is a Minelab Excalibur. It's water-proof and almost idiot proof when it comes to ease of use (I need that.

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My preference on a beach is a Pulse-Induction machine. They don't discriminate anything (exception being the White's TDI, but they're difficult to learn). PI's take a little bit of getting used to, but they are DEEP...mine will send you digging to China after the back of a tiny silver ear ring. With a little practice, the user can discern a hair pin from a good target almost every time...it's all about the sound.
7. Technique is everything on a minerialized beach. Obviously, a good ground balance can help. However, most good machines track and adjust ground balance on-the-fly. Some machines adjust more quickly than others, but none are fast enough to eliminate changing ground conditions totally.
If your machine has a track lock (MXT for example), turn it on after balancing.
Regardless, always make an effort to hunt perpendicular to the water line. In other words, hunt in-and-out with respect to the ocean. Swing slowly. These two actions will help negate the effects of crossing over pockets of the dreaded black sand which tend to run parallel to the water line.
8. General beach thoughts (Gosh! Does this guy ever shut up?):
Sand has a tendency on most beaches to accumulate between major storms. Keep an eye on the weatherman. When a major storm has hit a beach, you should be there at daybreak to beat guys like me. A major storm hitting a beach can remove several feet of sand...revealing many targets that were previously missed.
You mentioned tides. If you don't have a good tide program, here's one for a PC:
http://www.wxtide32.com/
Here's one for a Mac OSx:
http://homepage.mac.com/lrucker/XTide/
Use your newly gained information regarding the EXACT times of low tides and be there at least an hour before low tide.
Hope this helps.
(Below is a pic of "

lack Sand on the Santa Cruz beach.)