I have been using 4ft 2 bulb fixtures over my flasks and am starting to try some T5 fixtures. The T12 are 40 watt and the T5 are 54 watt. I am a bit vague on all of this, but my understanding is that T5 put out more light per watt than T12. Does anyone have any experience with converting? Could I get by with only 1 bulb T5 replacing 2 bulb T12?