MH Light Height

[ShipOFools]

Hey now just wondering if there is a rule of thumb for the height above your tank for mh light?

[Colin]

Everyone will say 8 inches, but you can go lower. The biggest issues with low placement are temperature (not that big a deal, my low MH is cooler than the VHO's I replaced) and light spread. A higher placement lights up more area, while a lower placement concentrates more light in the center.

You definitely want to have it high enough that it won't get splashed.

--Colin

[WarrenG]

A 6" difference in height will affect the intensity of the light that hits the surface by about 50-60%.

[xtm]

Mine's 10" above the water line. Anything lower and my chiller starts screaming.. ;)

There is no 'rule of thumb' that I know of when it comes to MH distance to the water.