Opinions on HPS to MH conversion lamps

Indoor Growing
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#1

Greetings!

Once I have my medical card, hopefully within the next 45 days, I will look to get my 2’x4’x6’7" tent stood up and my first legal medical grow up and running.

That being said, I have an older but relatively unused Sun System 2 400W HPS I have from many years ago that I will be utilizing for my grows until the ballast dies. Currently, I just don’t have the budget for a secondary grow light dedicated to veg or a decent full spectrum LED rig. Since this older model Sun System does not have a digital/switchable ballast, It would seem that my options for these first grows are to either run the HPS lamp for the whole cycle or get a MH conversion lamp like the one linked below if I want to provide the correct spectrum for each growth stage.

I realize an HPS ballast can fire a standard MH lamp but my fixture will not accommodate the large globe typical of a standard MH. In this instance, I need the MH spectrum in the form factor of an HPS lamp so the conversion is the best solution, i think.

I am curious if any of you have any experience running conversion lamps and what your opinion is of their performance. I will be growing autos and a lot of sources seem to indicate an HPS will perform nicely for both veg and flower. However, if I can keep the nodes a bit tighter and provide a slightly better environment for veg with a $35 investment, it seems like a no-brainer.

What are your thoughts? Thanks for the insight!

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#2

For 35$ it’s worth experimenting with. It will for sure put off the MH spectrum, what can go wrong? lol

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#3

I used to run Philips HPI-T 400W MH bulps, on regular cheap magnetic HPS ballasts for veg.
They work great for veg, and mix spectrum flower!

Id stick to a brand bulp, like Phillips, Osram/Sylvania or Hortilux if I was you.

2 Likes
#4

There was a time when most HPS bulbs were conversions cause all everyone had was MH ballasts. Close to 30 years ago but there was a time.

Haven’t used any HPS or MH in almost 10 years but they used to do OK. Can’t say I ever saw a difference between a HPS or the HPS conversion bulb other than I think 30 watts difference. Pretty sure the conversions are 30 watts more on a 400.

:wink:

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#5

Good advice. I ended up going with a Sylvania 64575, which I found for pretty a decent price.

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#6

Am I the only hacker who uses regular 1000W MH bulbs in my magnetic hps lamps in week 1-2? They do burn out a bit faster than normal tho :grin:

Edit, oops I missed the part where you mentioned it :+1:

#7

why do run the MH at first - to reduce stretch? I used a 400w Hortilux HPS bulb for vegetative for a couple years and had no problems, maybe the plants were a little taller but I didn’t notice. It’s way more lumens than the MH conversion bulb. MH bulbs were expensive & didn’t last as long as HPS.

there are some really cheap LED options for veg out there nowadays - any decent 5000K bulb or fixture should do. ooops, I was thinking of this one but it sold out

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#8

Yup, exactly. 6" difference can make or break me sometimes. I’m in a basement, on raised tables… and my reflectors are bolted to the ceiling, so switching to LEDs for veg would be difficult.

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#9

so the HPS ballast is able to ignite the MH? do you have smoke alarms down there :fearful:

A lot of people used to prefer MH for the whole flowering cycle, even before ceramic MH

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#10

Yup, as far as I know the only difference is that an HPS ballast has an igniter. Smoke detector in every room, my man. But I don’t think it’s an increased risk of fire. :+1: I’ve seen/heard about a lot of accidents when I was working at a growshop in my youth. Had a fan spontaneously combust on me once :fire: :worried:

#11

yikes, was it making noises or anything before? I worry about the little clip-on “hurricane” fans from Amazon, they seem shitty quality, it’s hard to find something that fits into a 4X4 tent

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#12

It was a honeywell oscilator. I went into the growroom after being away and it was melted into a pile on the floor. Thank God nothing else caught fire.

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#13

I think the majority of the grow fires we saw in the earlyer days, where stoners fucking around with electrisity they had no business fooling around with.
Now most buy plug n play and there is little wiring, or stoners got smarter over the last 20 years.

1 Like
#14

You’re right… they did become smarter Palindrome.
I was testing over time 4x ledlights and it was…Bull… not good at all.
Lately we were testing led and wowwwww… time is there that they can give enough to stop using HPS.
They are using that little power and they are more safe. Also less problem with the warmth.
The best I did find was on www.rubol.nl

Stay cool, SpeesCees

#15

Im also venturing into the LED world, but electrical fires are easy started with 12 or 24 Volt as well.
But the light won’t set the grow on fire, so yes the low heat is deffently also alot safer.

Im doing Strip light test atm, mainly for veg and HPS for flower. I might change to LED in the flower room, but at this point I got HPS and it works. Been away for 10 years, so a lot have happend and im sure I’ll catch up little by little.
But you know, old habbits die hard. Building a flower light for the closet, and we will see what happens.

#16

I use a conversion bulb. A mh in a hps ballast and love it. The mh runs cooler then the hips bulb. Mine is a Phillips metal halide for an hps ballast. I am looking at adding leds to my grow tent but I would not grow without both bulbs. You can go look at my grows and see why I use both. I have used just an hos for veg and flower. I found node space to be much larger then when I bought the conversion bulb they got real tight. Like I said, if I am going to use HID lighting I have to have both. I feel it makes that big of difference.

#17

I’m using a philips hps/CMH 400w bulb , it’s 360w real, so a bit more of the usual 315w LEC around today… The spectrum is LEC like, UV comprised so it’s a good alternative for existing good HPS setups with multiwatt ballasts.
I do anyway think it’s best use is for veg/start of flo., But after 20 days of 12/12, changing for a 600w HPS give a definitely better result.
Would be interesting to see what a 600/540w would do if they did it
A good buy , anyway…
DS