It's probably a good idea to keep extra lights on hand these days...

[MitchM]

I ran into the same kind of issue a couple of years ago with my Profilux.
The main control module fizzled out.
I tried to buy just a replacement control module, but they're only sold in kits. I was without control for my water flow, dosing, heating and water top off for 5 weeks.
I still need to get an extra control module just in case it goes down again.