Lighting - Loud Popping Noise!!

[sdascher]

I thought that may get your attention! I did the wiring myself as that is what I do for a living so I know that the lighting fixtures are safe. I tested them one by one when I mounted them and I used all teflon wire. This is my problem though - after I turn the lights off - 4- 50/50 smart lights that get really hot - the cooling down gives out these really loud popping noises! Scares the heck out of people! I am guessing that it is coming from the metal mirror reflectors of course, but I don't quite know what to do about it. Anyone else have this problem??? I use 2 clip on fans that run all of the time and the tank temp stays at 78 - which has worked out fine for me! I was thinking that maybe I need to remove the top and also each light reflector and maybe put some kind of heat resistant washer/padding behind it but I don't think that it will do any good as they are mounted on the wood top now..... and the metal will still get just as hot. Maybe I should just remove the reflectors??? Is there anyone out there using the mirror metal reflectors??? I would assume that most people do.....
I have 2 shutting down one hour before the other 2 and the same in the starting up.
Thanks - once again for any suggestions!

 

[reefnut]

Are they the reflectors that came with the lights or DIY reflectors? Removing them will cause a lot of light loss so I would try to fix them.
Do you thing it would help to put more fastening screws in the reflector? Sounds like when they get hot and expand that they are bowing up and when they cool they pop back into place. A few more screws may fix it.

 

[sdascher]

Thanks for the suggestion. I will have to do something as when you walk into my tank room after the lights go out - it sounds like someone is shooting at you!! I am going to remove the canopy this week-end and try to fix the problem. ( it scares the hell out of my hubby..... he jumps! I sort of like it in a sick kind of way...) Tee Hee........

 

[donjasper]

Well if the hot reflectors are cooling (and shrinking) could they be sliding past a sticky rivet or something? Are they screwed down? I'd think that the reflectors should be rather loosely mounted so that they could sort float around so they have room to expand and contract as they heat up / cool down. Maybe it's something else besides the reflectors cooling down sliding across something?
I'd try loosening all the screws half a turn and see if there's any effect.

 

[jarvis]

Do you have any type of fans running air through it? If you are building up enough heat for alumuminum expand and contract I would say that your building up enough heat to cause a major temp swing in you tank.

 

[marvida]

It's got to be some kind of expasion/contraction thing going on. Is your reflector mounted on offsets or is it mounted directly to the hood? A little extra silicone between the hood and the reflector might help.

 

[eric4usa]

I mounted mine to my canopy with like 5 or 6 washers between the reflector and the wood it's mounted on (washers on the mounting screws)
This gives like a 1/4 inch gap between the wood and metal and gives it enough room to expand/contract without touching the wood.
Plus the air space keeps the wood from getting excessively hot.

 

[sdascher]

Yes! Thats it eric4usa! Mine is mounted to the wood with wood screws, but when I mounted them I didn't put any washers on either side and they are tight against the wood. The wood doesn't really get too hot, but I can see where it does not allow the metal room to expand/contract! You got it for me!! Thanks!! I will fix those tomorrow!! Yes I do have fans to cool the lights, and glass tank covers and my tank does stay at temp. of 78. Room temp stays at 71 pretty much year round.