400 Watt HPS a few questions?

ok so i posted a thread before that asked whether or not all hps can run Mh bulbs or not and i had some statements that said yes,some said no,some said a bunch of stuff so heres my questions
1.Will my HPS run MH bulbs too(my firend just purchased a MH bulb)?
2.Will switching from a MH bulb to HPS cause any shock to a plant?
3.Any help would be appreciated +rep

Depends on your ballast...and type of fixture. There are horizontal MH bulbs and there are vertical...pick the right one for your fixture.

an HPS ballast wil run an HPS Bulb, a Conversion HPS Bulb or CMH (Ceramic Metal Hilaide) bulb. Not wont run a MH or a Conversion Metal Hilaide bulb.

a MH ballast will run a MH bulb or a Conversion MH bulb but not a CMH (Ceramic Metal Hilaide Bulb).

some ballast are switchable (mostly Electronic ballast) so they will run either an HPS or a MH, but you can not use an E-Ballast on a CMH (Ceramic) bulb. UNLESS the E Ballast specifically states it will run a CMH Bulb.


MH bulbs are more a a blue colored Veg bulb, while HPS is a red colored Bloom bulb. so using MH isnt as good for Blooming as a HPS is, and a HPS isnt as good a veg bulb as a MH is.

gobears4eva said:

ok so i posted a thread before that asked whether or not all hps can run Mh bulbs or not and i had some statements that said yes,some said no,some said a bunch of stuff so heres my questions
1.Will my HPS run MH bulbs too(my firend just purchased a MH bulb)?
2.Will switching from a MH bulb to HPS cause any shock to a plant?
3.Any help would be appreciated +rep

Click to expand...

It would depend on your ballast, all types will not accept either or bulbs. Some units require a conversion bulb, a special MH bulb that can work properly with a HPS ballast. If you know the brand of your ballast you can contact the company or place where you purchased it. I am interested in the CMH (Ceramic Mercury Halide) bulbs that can be used from vegging to flowering without having to switch bulbs. Based on what I have read about these bulbs they do not work with digital or electronic ballast. I don't know what mine is, but I think it is a regular/magnetic ballast. If your ballast is not compatible the bulb probably won't work.