Your best bet is to buy the dual spectrum hortilux bulbs.

But, if you dont, you want to run HPS to MH in a 2:1 ratio. This is critical during the flowering stage.

HPS emits ZERO UV B light, while MH emits a ton of UV B rays.

It is fact that UV B rays increase THC production. THis is why herbs grown at higher altitudes produce more THC than their genetic counterparts do at sea level.

MH should be the predominate source in veg, then in flower, HPS 2:1 over MH.

Even using several 500W Hortilux lamps, its still so wonderful to blast the lower sections of the plants with MH light during flower. They absolutely love it...and so will your brain.