Originally Posted by tamra&steven
if you have a 55 watt ballast it will only put 55 watts to your bulbs. so getting 65 watt bulbs wont do anything then under power the 65s
This is not necessarily true. If you have an electronic ballast, it will light up any bulb that is below the MAX watt rating. <That is because the ballast is load sensing.> A common ballast is 140W, and that is often used in the 2x55W fixture. That would be OK for 2x65W as well.
To be sure, you will need to open the case & read the ballast load rating. <Or at least get a parts number to google what it is good for ... >. If you have at least a 130W ballast, you should be able to substitute the 65W's.
<Note: Some site would flatly state that the 65W & 55W bulbs are interchangeable. This may be true as you can usu. overload a ballast a little .... However, the overloading increases heat & may burn out the ballast or create a fire hazard, so I suggest checking the ballast to be safe.>