MH mounting height.

[Pchromis]

Hi all,
When using a MH reflector or pendant which will be mounted in a canopy and you mount it 12" above the water, where is the 12" measured from?

The bottom of the reflector or the bulb itself?


Thanks

[cannarella]

I am pretty sure it is from the lamp.

[Pchromis]

Thanks, wasn't too sure as I've never used MH lights before