I run all my tanks on Excel and 2 watts per gallon. I like it as a medium tech, relatively low maintenance system. Very little algae problems, reasonable growth rates and fairly wide choice of plants.
It is kind of a myth that it is expensive to use too. You can buy a 2 liter bottle at Big Al's for 23.99 a bottle. That is 2000 ml. If you dose at the recommended daily dose of 3 ml for a 30 gallon then that bottle will last well over a year. Hardly a huge investment. I can't imagine CO2 is much cheaper than that either.
You can get a $20 Aqualifter pump and then the dosing is automatic too.
Good luck, Bill