How to remove protective cover from pool light

Kes

Well-known member
Apr 24, 2010
64
Worcester UK
We have a pool light some 9 to 12" below the water level. I think it is a Certikin PU6. It was fitted in 2008 so it the old sealed beam type. It has a protective cover behind which lurks some ugly algae. The cover is a loose fit and will spin round but be blowed if I can see a way of removing it.

The light has rwo screws in the fascia, aligned horizontally (which is why I think it is a PU6). There is what appears to be a knurled ring securing the cover, but this is quite tight and can't be moved by modest hand pressure. I am apprehensive about what will happen if I unscrew this or the two fascia fixing screws, I don't want the electrics to be flooded or water to escape behind the liner. I'm anticipating that it will be straightforward to remove either the cover or the entire bulb setup, and that this can be done underwater, so to speak. Can anyone who has done this before proffer some advice? Thanks.