doco: I read his thread. kd's T5s are 27watts. Growers would do better with the 54 watt (HO = High Output) set up.

This is the little that I know about floros in general that might keep things straight.

Every size of fluorescent tube comes in three power levels:

  • NO (normal output)
  • HO (high output)
  • VHO (very high output)


All you will see in Home Depot and Target are the normal output ballast/fixtures and the tubes that fit them. With T5 you want the 54 watts only as they are they throw more lumen power than your 27 watts, so check specialty light shops or aquarium shops or online. The prices are slowly coming down for T5 HOs to the point of being viable.

Ballasts come in two flavors:
  • magnetic
  • electronic
There are only electronic ballasts for T8s.
The "T" stands for "tubular", or the shape of the tube.