MH Bulb in HPS Ballast?

What is wrong with doing this? Don’t just say your not supposed to cuz it’s a fire hazard.

Ive heard people arguing both sides of this. Some say they do it with no problem. Some say it’s a fire hazard. The Sun System 4 accepts both and theres no fire hazard, but I don’t think its designed any differently than the original sun system, which I have(150 hps). I don’t see why I cant just stick an mh bulb in there.

Whats the deal with this? Can you safely operate a regular Mh bulb in a HPS ballast?
Also if you do this do you need to change wattage(ie. 175mh for 150 hps) or do you use the same wattage bulb?

conversion bulb

conversion bulb

you can buy a conversion bulb...jus look on the internet...they are about $60 to $80...htgsupply.com....peace djxx

sorry, you have a 150 watter

sorry, you have a 150 watter

i don't think they make conversions for that small of wattage..i think they start at 400 and up..but they(ballasts) have to match and the hps and mh ballasts are different...they do have digital ballasts that do both types of bulbs..peace again djxx

DJXXPLATINUM said:

i don't think they make conversions for that small of wattage..i think they start at 400 and up..but they(ballasts) have to match and the hps and mh ballasts are different...they do have digital ballasts that do both types of bulbs..peace again djxx

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Yup, I have one of the 400watt inter=changeable digital's... too bad I don't have a MH bulb though... damn!

If you're going to buy a light set up, I would buy the 600watters. They are reportedly superior to lower and higher watt rigs. It's been said EVERYWHERE that the 600watt set-ups have the highest watts/lumen ratio = best performance for your dollar/euro/yen/won/bot etc.

jchesmore722 said:

... I don’t see why I cant just stick an mh bulb in there...

Whats the deal with this? Can you safely operate a regular Mh bulb in a HPS ballast?

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Sorry, I missed this. I've read in different places that their are significant differences between the way these two bulbs operate. No, do NOT throw a MH bulb in an HPS only set-up or HPS in a MH set-up, this poses a fire risk FOR SURE. From what I've read, the HPS bulb is a bit more robust in it's initial arc load requirements. When you first turn a HPS on you may notice how for a brief moment nothing is happening, then you hear a click and the bulb snaps on. What this is is a phase of capacitance, or "charging up" where once a high enough state of power is achieved then the arc is allowed to kick in. After this point the bulb itself will warm up. From the little bit that I've read I know that both bulbs have different requirements in this initial, and post initial phase. I don't really know a whole lot about it, but I will say DO YOUR OWN READING TO FURTHER YOUR UNDERSTANDING OF THESE LAMPS BEFORE YOU EXPERIMENT WITH THEM, THEY WILL ABSOLUTELY KILL YOU AND YOUR UPSTAIRS/DOWNSTAIRS NEIGHBORS if you don't know what you are doing. These bulbs operate at combustible temperatures and are also under HIGH PRESSURE and have the potential to kill you by exploding. Also avoid getting ANY WATER ON A BULB IN OPERATION. This acts to rapidly cool an otherwise scalding hot glass surface. The rapid change in one isolated spot in comparison to expanded super hot regions around it will crack the surface and potentially allow for ALL THAT PRESSURE to escape in an explosive maner.

Always use your head before your hands. PLEASE, if anything else, BE SAFE

dude i know nothing about putting a MH bulb in a HPS ballast but i will say if you had to choose between using one or the other its highly suggested to just use a HPS through out the whole grow..

i personally have a switchable ballast which if i remember correctly wasnt that much more expensive to buy in the first place.


i have a buddy who uses HPS to veg as well as flower, his plants seems to take on a different look while in veg but over all we get a very similar yeild using the same strains/soil/ferts..

why risk a potential dangerous situation? or even something as simple as ruining your equipment?

sorry i couldnt answer your question but i hope this sheds some light on the situation.

best of luck to you man.

Hps ballast is capable of running a mh bulb, The thing is there's an ignitor in an hps ballast, This ignitor will decrease the life of the mh bulb, So it will work, Howver it will shorten the life of the bulb.

A switchable ballast, (RUNS BOTH MH AND HPS) is just an hps ballast with an on off switch for the ignitor, So when ya flip the switch to mh you really just shutting off the ignitor. This allows you to run an mh bulb safely on a hps ballast without decreasing the life of the bulb.

Again a SWITCHABLE BALLAST is just an HPS with a on off switch for the ignitor. When its set on mh the ignitor is doesnt get powered, When its on the hps side it does.

Also switchable ballast shouldnt even cost anymore maybe 10$ but thats all, I just purchased 4 1k switchables a few months back same 224$ as the normal 1k hps ballast!

Yeah its very possible to add a switch, So you can basically make it switchable.

Its as simple as cutting the line to the ignitor and adding a switch so you can break power to it. Then you have a switchable ballast that will run both.

Like I said thats how they make switchables to begin with.