i need a good mh conversion bulb!!!

SO I have an extra 400w hps ballast. got a 600w hps, now. Thought it might be a good idea to get a 400w mh conversion bulb and use this for veg. Does anyone know a good conversion bulb? Or do you think I should just get a 400w mh ballast w/ mh bulb?

http://htgsupply.com/viewproduct.asp?productID=52401

http://htgsupply.com/viewproduct.asp?productID=52141

You can use a MH bulb in an HPS ballast. You just can't use an HPS in a MH ballast.

I would have to assume there is a drawback to putting the mh bulb in the hps ballast. flicker or lower life. Has anyone put a mh bulb in a hps and had succesful results? I only question this because there is a reason why they make the conversion bulb.

#1 MH conversion bulbs are junk they don't put out as much light as advertised most of the time and are weaker than standard MH grow bulbs and usually have a weaker blue and violet spectrum.
Thats my own biased opinion.

I had a 600w HPS and I put a MH buld in it. It burned out after 6 months on a 18/6 hr use. The guy at the store gave me a new one cuz they're gaurenteed for a year but he said thats because of the wrong ballast.

Theres an ignitor(for lack of better words) needed for a HPS bulb. So you put a MH in it tries to ignite it and can cause wear. I never did it with 24 hrs light, the lack of on and off causing it to ignite may extend the bulb.


Get an 'electronic' ballast it'll run both bulbs, some have switches some don't.

Atwaterhydro.net

Has a 400w that runs both for about 150$ I deal with him all the time they have discreet shipping too. BUT I would EBAY the reflector and bulbs if u know what u need because he sells them seperately and it can all add up.

P.S. a GOOD ballast will have at least a 2 year warranty, KEEP YOUR RECIEPT. Even though they're made for growing plants they AREN'T made to run 24 hours and unless you really drop some bank on a good one keep your slip ANYWHERE you buy one.

huh great reply!!! Youve definitely gave me the answer I was lookin for. I dont need it to be switchable though all i need is 400w mh for veg. Have you or anybody ever used the high bay type mh. Basically the warehouse lighting. They got hundreds on craigs list by me for like $15 buks. Its the 400w ballast old crappy bulb and the round type reflectors. Seems like a good deal!!
I should just stop tryin to be cheap and buy some proper gear. I mean really i got like a grand easy in this project already and now im talkin bout bein cheap on a light. I dunno maybe im just too high right now. Wut u people think? I mean about the light not if im tooooo high!

Well I learned the hard way I got a bat wing deflector and my temp raised to 90 and i had to go air cooled so make sure you get one with an air cool option just in case. If you do get a fan I have a 434 cu ft per min. fan on my 600 and its still around 80 at the canopy in a 5 by 8 room. 600 should sufficiently cover 4'X4' max I have CFLs under neath to hopefully get the bottoms to fill in alittle more and strengthen the stems.

As far as the warehouse Metal Halide bulb yes it will work as long as its wattage doesn't exceed the wattage of the socket you get with the ballast.

Keep in mind these lights are designed for visibility not growing plants so the spectrum is going to be super suckfest, but it will work.


What I've learned in the last month is its cheaper to buy the right stuff the first time so you don't waste money on inefficient stuff you can't use.

Ebay has horticulture bulbs for 20-70$ that run 45-140$ in stores. Just get one of those, do some internet research for each brands color band(spectrum) Ideal for MH(Blue) is around 425nm and HPS(Red)670nm for.

Also its better to get one that has a higher orange content than green since chlorophyll is green and the plant actually reflects green light photons.

yeah i made my own cool tube from pyrex bake a round. you gettem on ebay for like 15 bucks. they work great. its a 4 inch glass cylinder. check em out for future use. i think im gonna get that high bay ballast and buy a new bulb. should work just fine. i was hopin to hear someone say they had success with th conversion bulbs but oh well.

Don't forget to open the box before you buy the Bay ballast and make sure it has an electrical outlet. Some of them are just wiresto be wired directly into your building or house wiring.

Keep in mine also, when dealing with an internal ballast it WILL get VERY hot, almost as hot as the bult, so make sure its not sitting on or attatched to anything that will burn.

I HAVE seen those burn THROUGH an end table, and burn off cheap aftermarket light hangers.

Make sure your chain or whatever your hanging with can hold up to 100+lbs this should ensure the metal is thick(strong) enough to take the heat.


Just my take becareful and have fun