Neptune Sky’s clicking

[Hilltop Aquariums]

I run 3 Neptune Sky’s on my 220 gallon and once in a while I hear them clicking. It seems like all 3 do it. They are in a canopy with the top and back open so they have plenty of air flow and I clean them once a month. Anyone else hearing clicking from there lights?

 

[CasperOe]

I run 3 Neptune Sky’s on my 220 gallon and once in a while I hear them clicking. It seems like all 3 do it. They are in a canopy with the top and back open so they have plenty of air flow and I clean them once a month. Anyone else hearing clicking from there lights?

I don't have the lights myself, but my Radion's do it as well. I had it down to slight thermal expansion over the course of the day, haven't thought to worry about it though..

 

[Hilltop Aquariums]

These seem to do it when they are ramping up. I’m wondering if there is a solenoid that turns the fans on?