400 ballast is mh or hps?

i have a 400 watt ballast, old kind of ballast a rectangle white box their is no writting on it what so ever but i am wondering if its for mh or hps bulbs is their anyway to know for sure before buying bulbs and if its for MH bulbs what happens if i put hps bulb?

Take it in to a pro and have it assessed for functionality and safety. Sounds like you have a magnetic ballast.

Jo162 said:

i have a 400 watt ballast, old kind of ballast a rectangle white box their is no writting on it what so ever but i am wondering if its for mh or hps bulbs is their anyway to know for sure before buying bulbs and if its for MH bulbs what happens if i put hps bulb?

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If you post a pic of it that may help us determine what kind it is, Usually MH have a smaller lighter ballast while HP is much heavier. If you know someone who has an old 400 watt hps bulb you can try that, I am sure the MH will light in the Hps ballast, but the MH ballast will not light an HPS bulb.

Bear420 said:

If you post a pic of it that may help us determine what kind it is, Usually MH have a smaller lighter ballast while HP is much heavier. If you know someone who has an old 400 watt hps bulb you can try that, I am sure the MH will light in the Hps ballast, but the MH ballast will not light an HPS bulb.

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I'd be slightly concerned that an HPS igniter may damage an MH bulb, but this is something I've never tested or seen examples of. Just a word of potential caution.

spek9 said:

I'd be slightly concerned that an HPS igniter may damage an MH bulb, but this is something I've never tested or seen examples of. Just a word of potential caution.

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That's more than likely good advice, I have lit an MH in a HPS ballast it did light it, not sure if there was any damage to light, but the light still worked okay, It may have taken some life from it.

Look inside. HPS will have an ignighter.

They are usually hps if they dont say. Get a conversion bulb to run mh

Just look inside and if there are 3 things it's HPS. Two and it's MH. I have been using a bunch of mags from 150 - 1000W for the last 20 years. Gone digital recently too.

If its a MH magnetic ballast can i use an hps conversion bulb? probably cant use regular hps bulb?

Jo162 said:

If its a MH magnetic ballast can i use an hps conversion bulb? probably cant use regular hps bulb?

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I would be making sure what type it is before running out and buying any bulbs for it. Have you had a look inside yet? There should be a info sheet on the big transformer inside to tell you what type it is and have a wiring diagram as they can be wired for a bunch of different voltages but likely 120 in north america. If it has a normal wall plug on the end of it's power cord then it's 120.

If the coil/transformer has only one component attached to it then it's MH. The one thing would be a capacitor and is in both types. If there are two things attached the other thing is an ignitor and is for HPS only. I recently replaced the capacitor in two of my ballasts as it's the most common component to fail. I also recently bought a multimeter that can test capacitors as they can be weak and that translates to reduced light output. My electricity cost almost 25¢/KWH so I want to get as much bang for my buck as I can.

Let me clarify you can run a MH bulb in an HPS ballast (same wattage of course) But not the other way around. A HPS bulb will NOT fire in a MH ballast. -HPS bulbs use an igniter to light whereas MH bulbs Don't.

It doesn't have a switch for MH/hps? I melted my last magnetic at the plug on the ballast. My digitals never did that.

Be extremely careful with hid lighting systems. Get that sheet checked and get the right lamp and use new lamps too.

Be safe

Bear420 said:

Let me clarify you can run a MH bulb in an HPS ballast (same wattage of course) But not the other way around. A HPS bulb will NOT fire in a MH ballast. -HPS bulbs use an igniter to light whereas MH bulbs Don't.

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That's why if an HPS bulb won't fire in an HPS ballast but an MH bulb will then the ignitor is shot but the coil and capacitor are working. I've never had an ignitor fail but have had to replace a few capacitors in the last 20 years.

I have a 1000W MH/HPS switchable magnetic ballast that died and wouldn't fire either bulb. Got a new cap for it and it works fine for both now.

OldMedUser said:

Just look inside and if there are 3 things it's HPS. Two and it's MH. I have been using a bunch of mags from 150 - 1000W for the last 20 years. Gone digital recently too.

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Here are some pics. It says Metal halide balast on sticker so i figure its an MH balast XD wich brings me to my next question if i use an hps conversion bulb will it work with this ballast?

It looks like it says metal halide.

Conversation bulb will work.

Jo162 said:

Here are some pics. It says Metal halide balast on sticker so i figure its an MH balast XD wich brings me to my next question if i use an hps conversion bulb will it work with this ballast?

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That is an MH

Jo162 said:

i have a 400 watt ballast, old kind of ballast a rectangle white box their is no writting on it what so ever but i am wondering if its for mh or hps bulbs is their anyway to know for sure before buying bulbs and if its for MH bulbs what happens if i put hps bulb?

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it wont light up if its a MH ballast,i tried didn't work,has to be a MH bulb if it is a MH ballast and vice versa for old school ballast

Jo162 said:

Here are some pics. It says Metal halide balast on sticker so i figure its an MH balast XD wich brings me to my next question if i use an hps conversion bulb will it work with this ballast?

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It's definitely an MH ballast so any bulb you buy should specify that it works on an M-59 ballast. I have the same 400W one here but never bought a conversion bulb for it. I have 400W conversion bulbs to get MH light from HPS ballasts and a sweet 940W Hortilux conversion bulb the size of an American football to get HPS light from my 1000W MH ballast. I think the coil is dead in that one but have a 1000W MH/HPS magnetic ballast I can run it on.

A HPS conversion bulb will cost more than the standard HPS bulb because it has the ignitor built into the bulb and needs that to initially fire up.

Almost 20 years ago I bought 2 - 400W Hortilux conversion bulbs to get MH light off one of my 3 HPS ballasts. I used one of them almost constantly 18 hours/day for 15 of those years and it still works tho the tube inside has a blister on it now. Plants seem to like it. A couple months ago the wife was digging around in some old boxes and found the 2nd one that maybe got used for one grow and it still works fine and is in much better shape. They were $126.95CAN each 20 years ago but damn good bulbs.

That SunMaster, Warm Deluxe Metal Halide is for flowering off the same MH ballast as that huge Hortilux bulb but under my light meter has less than half the intensity at the same distance.

HPS igniitors are like 15$. Not sure howmuch conversion bulbs are, but i recall hearing they are less efficient. Wouldn't it be possible to throw an ignitor in there or does an MH ballast not have the extra (blue?) wire for it?