Answer: Yes.
Too much phosphates is bad, too little is also bad. You want to keep it at a level somewhere between those two extremes. "Too much phosphate causes algae" is a catchall from a less enlightened time in planted tanks, when people would more or less make something up and run with it. Too much of anything will cause issues, but eliminating phosphate, especially in a low CO2/high light tank, will cause an outbreak of Green Spot Algae.
If your going to put CO2 on the tank, 2xT5HO will be a robust amount of light. Without CO2, I don't know if it would be worth it because you would eventually have algae that would wouldn't get with lower light, but not get especially better results.
If you want to get pressurized CO2, it will cost ~$150, but you will find that it is the best investment you will ever make for a planted tank.