What size tank do you need the fixture for?
If 135 watts of CF was getting the job done for you, then IMO 108 watts of T5HO with a decent reflector should, as well. 108 watts would be a 2x54 watt fixture, if you're looking at 48" tank. (Though the 4x54 watt Catalina Solar T5HO fixture is the best deal ATM. I still love my Catalina Solar

)