Difference

[SmokeyB]

What's the difference between a hps light and CMH light

 

[TorturedSoul]

Technology; HPS is high pressure sodium, and CMH is ceramic metal halide. (They're both HIDs, though, and require a ballast to fire/run.) Newer CMH bulbs output a spectrum that is closer to natural sunlight than HPS.

 

[SmokeyB]

Do the cost most electric if it's same watt??

 

[TorturedSoul]

If the wattage is the same - and assuming equal efficiency for each ballast - then they'd cost the same to run. A watt is a watt, a kilowatt-hour is a kilowatt-hour.

 

[SmokeyB]

If the wattage is the same - and assuming equal efficiency for each ballast - then they'd cost the same to run. A watt is a watt, a kilowatt-hour is a kilowatt-hour.

With a 600w air cooled light? For 4 plants??