Tank's Worth

I've decided to sell my tank but I don't know how much the stuff is
worth. Can anyone give me a clue? I know how much I paid for it, but
it's not nearly worth that . . . I'm planning on getting a few smaller
tanks in exchange for the big one.

I have a 75 gallon tank with an oak canopy and stand, I have a
hamilton lighting system, ballast, 2 110 VHO and 2 halides. I also
have two brand new VHOS. I would say the tank and the lighting system
are about 3 years old. The halides need replacing, they work but
they've not been replaced in about a year.

Any ideas? I'm keeping the live rock, animals, filtration, etc. for
the small tanks.