light keeps turning on and off

[achillesheel]

ive got 4 mh over my tank (2 400w and 2 250w). all ballasts are pfo. the 400w are electronic and the 250w are magnetic. one of the 400w keeps turning on and off. i cant seem to figure out why.

any suggestions?
shad

 

[Toddrtrex]

Did you try switching out the bulb? Just so that you will be able to narrow it down to if it is the bulb or ballast.

 

[jgsensor]

As crazy as this sounds, I had that same problem and it was caused by the wall outlet. I switched the ballast to another outlet and the problem stopped. Other ballasts, pumps, heaters, etc worked fine in the suspect outlet, but for some reason the one ballast did not.