250W HPS vs 400W MH

Hey all!

So there are these two fixtures, already owned, but I am wondering which one would be better?

I am fairly experienced, yet this one racks my brain constantly.

I have always been afraid of using the MH because of no glass below it in the reflector. Does anybody use bare bulb - no glass shield- with MH bulbs? Is it scary? You read on the box about how it can hurt you blah blah, I understand HID lighting, very well actually, but this I do not.

Is it safe? Is the 250 HPS better in results of yield and output?

Thanks!

project fuoro said:

Hey all!

So there are these two fixtures, already owned, but I am wondering which one would be better?

I am fairly experienced, yet this one racks my brain constantly.

I have always been afraid of using the MH because of no glass below it in the reflector. Does anybody use bare bulb - no glass shield- with MH bulbs? Is it scary? You read on the box about how it can hurt you blah blah, I understand HID lighting, very well actually, but this I do not.

Is it safe? Is the 250 HPS better in results of yield and output?

Thanks!

Click to expand...

Why dont you just get a 400 watt hps conversion bulb.

The 400 halide would outflower the 250hps. Raw power with so many more lumens.
People use 1000's without a cover, no big deal.

OregonMeds said:

The 400 halide would outflower the 250hps. Raw power with so many more lumens.
People use 1000's without a cover, no big deal.

Click to expand...

To the first post, conversions bulbs look appealing, but the access I have to those vs. standard bulbs for almost nothing. Do you feel they truly perform better? If so, I will research it greatly. If not, what else can you suggest?

I do have access to 400hps for almost nothing as well, I am leaning more and more towards that direction. its only a 30x30"x60"

8" pot size. 9 of them in there, that only get 12"-18" tall anyhow. Would there be a great difference between the 400 hps vs the 250 hps? I know it is brighter, as I said I do have experience, but these are the issues that keep me awake at night. You feel me?

I even have a 1kw, but I don't want to be that big or cover that big of an area, even 4'x4' is too big. I am lazy and dont need lots.

project fuoro said:

To the first post, conversions bulbs look appealing, but the access I have to those vs. standard bulbs for almost nothing. Do you feel they truly perform better? If so, I will research it greatly. If not, what else can you suggest?

I do have access to 400hps for almost nothing as well, I am leaning more and more towards that direction. its only a 30x30"x60"

8" pot size. 9 of them in there, that only get 12"-18" tall anyhow. Would there be a great difference between the 400 hps vs the 250 hps? I know it is brighter, as I said I do have experience, but these are the issues that keep me awake at night. You feel me?

I even have a 1kw, but I don't want to be that big or cover that big of an area, even 4'x4' is too big. I am lazy and dont need lots.

Click to expand...

Get the 400 watt hps then. and of course the 400 watter is better any day than the 250 because it produces more lumens thus a better yield.

nxoro8x3 said:

Get the 400 watt hps then. and of course the 400 watter is better any day than the 250 because it produces more lumens thus a better yield.

Click to expand...

How much hotter is the 400 vs the 250? any idea? I cant imagine it being that much more, maybe creating a higher temp of -+5 degrees maybe 10.

Heat is no issue, as the 250 has been as low as 3" away, no cooltube. just good venting and cool ambients.

My vote is for the 250w HPS hands down. HPS's generally have more lumen output than MHs, watt for watt. A 250w HPS is about 30,000 lumens, and 400w MH is only about 40,000 lumens. Plus HPSs have better spectrum for flowering whereas MH bulbs are better for vegging. With the negligible difference in lumens coupled with the better spectrum in the HPS, I personally believe the results will be dam near the same. Since the 250 will generate less heat, and consume less power with almost the same, if not better results, my vote goes for the 250HPS. I have a 400w HPS (58,000 lumens) in a 55.5X36X24 inch area, and temps stay and a consistent, unconfortable 85F.

project fuoro said:

How much hotter is the 400 vs the 250? any idea? I cant imagine it being that much more, maybe creating a higher temp of -+5 degrees maybe 10.

Heat is no issue, as the 250 has been as low as 3" away, no cooltube. just good venting and cool ambients.

Click to expand...

Yeah thats about right.

LVsFINEST said:

My vote is for the 250w HPS hands down. HPS's generally have more lumen output than MHs, watt for watt. A 250w HPS is about 30,000 lumens, and 400w MH is only about 40,000 lumens. Plus HPSs have better spectrum for flowering whereas MH bulbs are better for vegging. With the negligible difference in lumens coupled with the better spectrum in the HPS, I personally believe the results will be dam near the same. Since the 250 will generate less heat, and consume less power with almost the same, if not better results, my vote goes for the 250HPS. I have a 400w HPS (58,000 lumens) in a 55.5X36X24 inch area, and temps stay and a consistent, unconfortable 85F.

Click to expand...

He said that he can get 400 watter hps for cheap so then he should get that 1 right its gonna be around 50 - 55k lumens.

If you can get 5000 lumens per square foot with the 250w HPS, then use the hps. If not use the mh.

I use a 400w MH conversion bulb and it is FANFUCKINGTASTIC!! Bright as all get out and gives me awesome results Then I switch the bulb to a 400w HPS and continue the success

im going to be using a growlux 400w dual spectrum hps for veg then switch to a 600w hps for flowering ina cupboard 1m by 0.8m and high as the roof hoping to gain good yield with this, how many plant do u think i will fit in this cupboard as i dont want to overcrowd and have to kill any as i am using all fem seeds they costing me like £5 a seed roughly £10 each for some of the better ones?

PPP Pure Pothead Person said:

im going to be using a growlux 400w dual spectrum hps for veg then switch to a 600w hps for flowering ina cupboard 1m by 0.8m and high as the roof hoping to gain good yield with this, how many plant do u think i will fit in this cupboard as i dont want to overcrowd and have to kill any as i am using all fem seeds they costing me like £5 a seed roughly £10 each for some of the better ones?

Click to expand...

I use 1.5 square feet for each plant i grow them to be about 20 inches tall

Thanks everyone,

I have yet to decide for sure what to do. What I am trying to avoid is buying things online, etc. I am skeptical.

I am interested in digital ballast, if i do have to purchase something.

Would 600W digi be overkill for a 6.25 SQ ft area, (30"x30"x64")/

Temps with a 250 run about 70-75f

Then one ends up having to buy bulbs repeatedly, etc, etc.

Do you see what I mean? Trying to make the best out of what I have.

Thanks for everybody's input!

Surely something will spark...

such as an idea

Dam, my hydro shop carries the Galaxy ballasts and I got a Sun System one instead! Wtf! I've never heard of a digital ballast before tho. Wish I would have known... Oh well.

Anyway, on to your question. I personally think 600w is overkill for that area. And this is coming from somebody who has a growspace of similar size (55.5X36X24) too.

See pic below...

400w HPS = 84-85F

I keep the fan on low tho, because it's waaay too powerful for my application, I need a bit of stealth.

But don't get me wrong. 600w in this area is possible, just overkill.

LVsFINEST said:

Dam, my hydro shop carries the Galaxy ballasts and I got a Sun System one instead! Wtf! I've never heard of a digital ballast before tho. Wish I would have known... Oh well.

Anyway, on to your question. I personally think 600w is overkill for that area. And this is coming from somebody who has a growspace of similar size (55.5X36X24) too.

See pic below...

400w HPS = 84-85F

I keep the fan on low tho, because it's waaay too powerful for my application, I need a bit of stealth.

But don't get me wrong. 600w in this area is possible, just overkill.

Click to expand...

If i can be cooled, why is it then overkill?
Seems to me, even if you could put a 1000W hps in there and cool it, all would be well. How can we possibly give it too much light? I need more info on this topic, if anybody has it.

Very interested in this too much light business... I have a 1kw, though the ballast seems to have rusted on the top or showing slight signs of rust, perhaps this is bad.

Anyhow... Let's hear it!

Because heat is not only in the air which you can exhaust, it's also radiated into the plant and can't be avoided. You'll just make them sweat so bad that a smaller light would have grown better.

Plus the bigger the light you cram in there, the less vertical space you have left for plants before they burn.

OregonMeds said:

Because heat is not only in the air which you can exhaust, it's also radiated into the plant and can't be avoided. You'll just make them sweat so bad that a smaller light would have grown better.

Plus the bigger the light you cram in there, the less vertical space you have left for plants before they burn.

Click to expand...

You make an excellent point OM, and I agree. However, does the heat issue outweigh the radiant intensity issue?

I am sure its somewhat scientific, but the general idea will fulfill what i need to know.

I am afraid of the MH lamps cuz the warnings seem crazier on the MH than the HPS. Why is that? Saying they can explode, blah blah, the hPS doesnt say that, and the UV rays it can emit if the outer layer is broken, blah blah. I don't wanna put anything in an air cooled anything. Hexagon reflector-250W can sit right on the tops and cover a good 2ftx2ft area.

But what is the penetration? Can It handle 2ft plants? Or lst'd plants? What is the best strain for this? I am stuck on the 250WHPS, if not, then a 400W, but I am thinking digital, and it seems they are not so good?

Ok, well, I rambled, sorry...

i would use both