Conversion lamps??

Hey guys was just wondering about the conversion lamps that are out there for sale. They say MH conversion globe so does that mean it converts HPS into MH? Or MH into HPS?? Thanks in advance guys really appreciate it.

The bulbs are not convertible. It's the ballast. The bulb is compatible with a conversion ballast.

They do make conversion bulbs as well. Bulbs specially made to work in the other type of ballast. They also make alternate color spectrum bulbs, and supposedly dual spectrum. They are quite a bit more expensive, like more than buying the 2 seperate types of bulbs, so only useful if you have a non convertable ballast, or I guess more balanced light in the case of the dual spectrum.

"conversion bulbs" is just a marketing term. They now make MH bulbs that run at 600w which is not a wattage that any manufacturer makes a dedicated MH ballast for. For all intensive purposes it is just a MH bulb - for the mere reason that is it not 250w, 400w, 750w, or 1000w, it is considered a "conversion" bulb. It's a MH in every way except for the wattage rating (600w) which has generally always been a HPS wattage only.

That could be correct, and I'm just confusing terms. Never researched the designs, just seen the selections.

Oh ok didn't realise that, I guess to those answers I have another question. At the moment I've got a 400w HPS (non conversion) and I would like to use MH for veg, can I buy a mh ballast and just plug my HPS lamp holder into the mh ballast? Obviously I'd have to get a new globe but could I use the same lamp holder for mh and HPS?

dazzledstars said:

Oh ok didn't realise that, I guess to those answers I have another question. At the moment I've got a 400w HPS (non conversion) and I would like to use MH for veg, can I buy a mh ballast and just plug my HPS lamp holder into the mh ballast? Obviously I'd have to get a new globe but could I use the same lamp holder for mh and HPS?

Click to expand...

Lamp holder? The cord/socket? Most all cords/sockets are universal although some super cheap low wattage cords/sockets should not be used with with higher wattage ballasts. If its a 400w cord/socket then it will work on a 400w MH ballast as well as a 400w HPS ballast as long as they are compatible plug types.

What type of ballast do you have? Most all newer digital HPS ballast run both MH and HPS. You might not need a separate ballast.

Gastanker said:

Lamp holder? The cord/socket? Most all cords/sockets are universal although some super cheap low wattage cords/sockets should not be used with with higher wattage ballasts. If its a 400w cord/socket then it will work on a 400w MH ballast as well as a 400w HPS ballast as long as they are compatible plug types.

What type of ballast do you have? Most all newer digital HPS ballast run both MH and HPS. You might not need a separate ballast.

Click to expand...

Yeh mate talking bout the cord/socket, I brought it as a kit of eBay the title said '400w HPS grow light kit' all the ones that are HPS/MH interchangeable usually say it in the description so I'm pretty shaw this ones just HPS, there's nothing digital on it as in a digital screen or anything, it's just a white rectangle box with a cord output which the cord/socket connects to, I think the brands growlush

dazzledstars said:

Oh ok didn't realise that, I guess to those answers I have another question. At the moment I've got a 400w HPS (non conversion) and I would like to use MH for veg, can I buy a mh ballast and just plug my HPS lamp holder into the mh ballast? Obviously I'd have to get a new globe but could I use the same lamp holder for mh and HPS?

Click to expand...

Just change the bulb from HPS to MH in your current setup. Your 400HPS ballast will fire a regular MH bulb with no problems. But a 400MH ballast will not fire a HPS bulb as it has no igniter. Conversions bulbs are just another marketing ploy for the most part.

phillipchristian said:

The bulbs are not convertible. It's the ballast. The bulb is compatible with a conversion ballast.

Click to expand...

AgroMax 400 watt Metal Halide CONVERSION Bulb
Product Number: LAM-AM400CON



This is an MH bulb, designed for use with 400 watt HPS (high pressure sodium) magnetic ballast or a digital ballast systems.

Use for Lush, Compact vegetative plant growth! 6500K!

High Output = 38,000 lumens !!! (Standard 400 MH bulbs only emit 36,000 lumens)

UNIVERSAL POSITION - operates in any position including horizontal

One Year Warranty

This bulb is perfect for growing plants during the vegetative stage. It's bright white light spectrum facilitates rapid, green plant growth! Growers worldwide agree that growing with Metal Halide during the vegetative stage, then switching to High Pressure Sodium for flowering is the way to grow the BEST PLANTS POSSIBLE. This method give you the thickest, most lush plant and the best yeilds!


This is a specialty horticultural bulb designed and manufactured for plant growth!

For use with 400 watt HPS Magnetic ballasts or Digital ballasts only.


Grow with the best. Grow with AgroMax brand grow bulbs!

Agro Max bulbs are about as crappy as they come...wouldnt recommend them to anyone.....

Ok so a couple of interesting things there been said. Firstly I was under the assumption that connecting a MH bulb into a HPS ballast would effect the efficienty of the ballast and as it was not made for this the globe could blow?? I mean why would they make specific HPs/MH Ballasts if all you needed was a HPS to run both??

Also it seems there's mixed opinions on the MH conversion bulbs, the one above is pretty much the same bulb I was originally speaking about, maybe I'll just buy one and see if it works in my HPS, there listed at only $30 on eBay

cowboylogic said:

Agro Max bulbs are about as crappy as they come...wouldnt recommend them to anyone.....

Click to expand...

It was only used as an example of what a conversion bulb actually is, and that actual conversion bulbs do exist and that it is not just all ballasts as was said in the message I was reply to.

If you would prefer an example from another manufacturer, that can be done. The AgroMax was just the first one to pop up, so I used it.

dazzledstars said:

Ok so a couple of interesting things there been said. Firstly I was under the assumption that connecting a MH bulb into a HPS ballast would effect the efficienty of the ballast and as it was not made for this the globe could blow?? I mean why would they make specific HPs/MH Ballasts if all you needed was a HPS to run both??

Also it seems there's mixed opinions on the MH conversion bulbs, the one above is pretty much the same bulb I was originally speaking about, maybe I'll just buy one and see if it works in my HPS, there listed at only $30 on eBay

Click to expand...

So they can sell you more equipment. The only difference between mag HPS and MH ballasts is the igniter. And the igniter only cycles when called upon to initially fire a HPS bulb, once fired it is no longer part of the loop. When you screw a MH into and HPS the ballast the igniter does not even come into play...

Brick Top said:

It was only used as an example of what a conversion bulb actually is, and that actual conversion bulbs do exist and that it is not just all ballasts as was said in the message I was reply to.

If you would prefer an example from another manufacturer, that can be done. The AgroMax was just the first one to pop up, so I used it.

Click to expand...

Figured as much, just didnt want alot of folks going off buying that crap since they saw it in one of your posts....

cowboylogic said:

So they can sell you more equipment. The only difference between mag HPS and MH ballasts is the igniter. And the igniter only cycles when called upon to initially fire a HPS bulb, once fired it is no longer part of the loop. When you screw a MH into and HPS the ballast the igniter does not even come into play...

Click to expand...

Ok awesome well thanks a bunch mate you just saved me paying for a new MH ballast!

No worries dazzle...spend the saved cash on some supreme genetics..........