Do I need a new equalizer?

Karla, Equipment and water especially SALT water (AND SALT AIR) don't mix very well. The constant high moisture environment affects all the connections (the wires) the rca connectors (where one thing plugs into another, AND the switches. The wires may LOOK good but the connections may not be. When you say "all seems to be in good condition" tell me specifically how you checked them. Sometimes they LOOK good, but ar not making connection. While your stereo is ON, get in there and wiggle everything and see it the speakers come back on.

My first guess is your amplifier/reciever. Does it have speaker switches? If it does, move them up and down or click them many times to see if you can work the corrosion a little. This may help.

I'll try and help, let me know some of the stuff I've asked fo above.