Manufacturer Bulb Type Pressure Type UV Spectrum
Aqua UltraViolet   Medium Pressure 185 - 400 nm
Emperor Aquatics T5, T5-HO Low Pressure 253.7 nm
WLim T5, T6 Low Pressure 253.7 nm

Bulb Type Rating

The "T" in this rating states the tube type, being Tubular, and the number represents the thickeness, being measured in 1/8th in. (e.g. T6 = Tubular, 6/8 in. diameter)

Pressure Type

Low pressure puts out a very narrow area, yet a high level of UV light at 254 nanometers. The medium pressure lamps don't put out a very high level of UV, yet they do produce a very broad range of UV over the entire spectrum that enables it to potentially kill more types of Microorganisms.

UV Spectrum

The UltraViolet light transmits a specific light spectrum that damages the Algae and possible protozoan's within the water.