So I spent three weekends diagnosing a new LED Pool Light that kept tripping my GFCI breaker. I re-wired the outdoor circuit box, I changed to an incandescent, I tried a different LED pool light. No matter what, inevitably after a few days of getting it all to work, my GFCI would eventually trip - and keep tripping thereafter.Finally I realized that water was somehow getting into my old Pentair Light Housing fixture. Of course I assumed water was coming in from my lens gasket. So I bought two new lens gaskets and tried them both. Still water was getting in the housing somehow. After many hours and many different steps taken to resolve the issue I finally realized that it was something else.Turns out - the fixture was leaking water into the housing from the wire that went into the back of the housing itself. I suppose that over several years of sitting in water and going through Michigan winters, that the seal eventually goes bad where the wiring enters the fixture.Installing this new Pentair fixture was simple.I cut the wire to the old fixture off near the housing and soldered the new wire to the old. Wrapped it in electrical tape and pulled on the old wire where it entered the outdoor circuit box. I never even had to drain my pool. I pulled this new wire up with ease into my circuit box and had plenty of extra wire left over. Wired everything in and boom, light was working, GFCI was happy and all is well after more than a week in the pool.I did open up the this housing when I first received it and replaced the 400W incandescent that comes pre-installed to a multi-color LED (https://smile.amazon.com/gp/product/B071ZD3PPC/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1) and everything works great. Also that light is bright enough for my in-ground 20x40ft 40k Gallon Pool.If you're ever in doubt about your wiring and wonder if water is getting in there, you will notice that the copper wire has blackend by the water getting into the insulation/wiring. *see pics attached* The wire should be a shiny bright copper color if no water has gotten into the electrical line.Hope this info helps someone else save lots of time. For the $179 I paid for this - I wish I would have replaced this as the first step in my trouble-shooting process.