On Fri, 2 Jul 2010 17:59:35 -0400, RBM wrote:

The bulb inside the fixture shouldn't be in any water.
Now that it is fixed, I finally realize that fact. Water was leaking in,
and taking about 5 minutes to flip the GFCI.

If it is, the seal on the fixture is bad
That solved the problem. I didn't see anything wrong with the old seal,
but, I put it back on twice and water still leaked in, so I replaced the
Hayward seal (even though it was an American Products light assembly) and
that solved the problem.

One question I have is HOW TIGHT to make the steel band. The tightening
screw is about two inches long and I tighted it until it wouldn't go any
further but I don't know how tight to make it since it "sealed" in the
first quarter inch, but I kept going for about 2 inches.

most likely the entire fixture needs to be replaced.
That's what the pool supply store said but it was the seal.

The GFCI is tripping because the bulb is in the water.
It's interesting that it was ALWAYS in the water (the leak was always
there, not just when I turned the lights on) but that it still took about 5
minutes after resetting the GFCI before the GFCI tripped again. You'd think
it would trip right away, not 5 minutes after resetting as the light
fixture was half full of water.

You can disconnect each fixture individually at it's deck box
I have no idea where or what a "deck box" is ...