Pool Ligt Fixture
Background: I am year two into my used pool that i got in a house purchase last year. Additional historical info can be found at "Swamp to pool conversion" thread (swamp-to-pool-conversion-t34542.html) I started in the summer of 2011. Briefly, the pool had been untouched for 1.5 to 3 years (except for reports of city workers dumping chemicals to keep mosquitoes from breding), was a deep dark green color (actually near black) prior to 2011.
Fast forward to today, it is a useful pool thanks in great part to the advice received from this forum. It is not perfect by any means, the liner is in need of replacement and pockets of dirt continue to form in predictable locations despite filtering, vacuuming to waste, or using an external pool vac.
That brings me to today's dilemma. The pool has a Sta-rite (Pentair) SunLite LTC (http://www.staritepool.com/pdfs/SunLiteOM.pdf) light fixture. When I was able to get to the light last year, I pulled it out of the pool and the light housing was completely full of green water. So, I took it apart (removing the clamp), cleaned the inside of the housing, cleaned the lense, purchased a new gasket and a new lamp. Upon reassembly, and after some troubleshooting, the lamp worked great, great until I put it back into the pool where it eventually (a day or two I beleive) filled with water again and the lamp would not light.
Since then I have tried a half a dozen or more times to get it to work for longer than a day, in the pool, but with no luck. I finally noticed a small pinhole in the housing that when I scratched, has produced a hole the size of a dime. I have tried to fill the hole with various substances and have reassembled the fixture, but water still gets in after 10-15 minutes of submersion.
There is also a metal band that seems to be part of the fixture (it seems to go in between the lens and the housing), but it is not listed in the parts manual that I found for the light fixture. The fixture fills with water if I assemble the fixture with or without the band (though it seems to leak slightly more WITHOUT the band).
At this point I am not sure if water is getting in through the hole in the housing (which I have currently attemted to seal with hot glue) or if it is entering through the gasket. The gasket does seem to be a slight bit big for the housing and the lens does not fit very snug, but I assume it tightens up a bit when the housing clamp is tightened aginst the face ring. I do not see any air bubbles form while the fixture is submurged.
I would like to isolate the problem and then get a good plan to fix it. So far I seem to be guessing wrong. If anyone has any advice or experience in this area, I would be greatful.