Talking to someone who installed some of them on Fork, those green lights should be run a certain number of hours a night to keep them cleaner. If you use one of the drop lights, you would probably want to make it where it is easy to remove once in a while to clean the algae off of it so need to keep that in mind for anyone figuring out the best way to permanently install one.

Rain-X works great, it fills the pores in the PVC. That is only if you put the light in a tube and seal it.

David