Lightbulb's Keep blowing out????

[jrang]

Hi,
I have a 4 perfecto 36" light strips over a 150 gallon tank. I have been attempting to change the bulbs and every time I turn the light strip on the bulb blows out on one side! I have just gone through 3 bulbs trying to replace them.
They are the same wattage and and I have used these bulbs(TROPIC SUN 15 Watt 18") for the last two years. This is a freshwater tank.
I am not sure what is causing this. Does anyone have any suggestions.
Thanks in advance.

 

[republicanreef]

Try changing the ballast - the black heavy box in the center of the light,

 

[jrang]

Thanks R.Reef! I appreciate the feedback.
If each light strip holds two 15 Watt bulbs would you buy a 15Watt ballast or 30?
Can I pick up a ballast at H. Depot?

 

[waterwolf]

The ballast will be a dual bulb ballast 15watt bulb. It is marked right on the ballast. Of course there are elctronic & magnetic ballasts too. Also does your lighting have starters or are they rapid start ballasts. I would check your ballasts and match them up before you buy a replacement. Also check your endcaps and wiring too, just to make sure they are ok. It seems like a small ballast but I am sure Lowe's or Home Depot will have them.

 

[republicanreef]

I agree, just disconnect the ballast in the light. It ought to be a black box looking object. Take it to a hardware store and try to match it up. It may be the starters which are cheaper, but they usually dont blow bulbs when they are bad.

 

[cadbury]

It's definetly the Ballast, I had the same problem and went through a few sets of lights. Relace the ballast, solve your problem!

 

[jrang]

Thanks for all the replies!
As soon as I dig myself out from all this snow, I am off to home depot to look for a new ballast.