After seeing some of the nasty things others at TFP found in their light niche I wasn't looking forward to replacing a burned out bulb. Found time to tackle it today. I understood the basics of removing the light, saw pictures on here of how the cord reached to the deck.
Good news, while there was some sand and grit upon removal the niche seemed clean. Sand was setled on the wiring. We live in a desert wash area so some sand is not unexpected.
When I took the hose and washed the back of the chrome ring/lens area I got 5 seconds of some black runoff and then 30 seconds or so of what you would say was foamy water, then all clear.
If it was mold or algae there wasn't much of it, do not believe light has been touched in at least 5 years, probalby 9 years, pool built in 2004 by previous owners. Not too concerned but I will pull light and check after a while.
Anyway, made my first Leslies purchase in quite a while, they had the bulb and a new gasket. Proce seemed OK compared to online also, $24 for both. That and a new brass screw from Hope Depot for 50 cents and we have light again!
Usually my home projects have bumps in the road, this one went pretty well!