12 Inches is the standard from the bulb to the water, I would suggest at
least 6 inches between bulbs. Why not upgrade to 400 MH ???
Run 20K bulb and you get better color, You can run a Digital MH ballast and
cut your cost too, cheaper in the long run - they save you on hydro plus
they let your bulb last longer


"Dave Keyes" wrote in message
nk.net...
Hello group,

I have been considering adding some more light to my existing hood over my
75.

I currently have ( 2 ) 175 w 10K MH and ( 2 ) 65w Actinic bulbs.

I would like to add some more PC lights and have the room to physically put
them in there but they will be close to the MH bulbs.

How close is TOO close?

TIA

Dave K