2 250's or 1 400 for 6sq ft?

[MedGrowerTom]

My Flower side is 3ft x 2ft x 6ft . I am using a screen this go around, and was wondering what everybody thinks I should do. I have 2 250 hps that I could use, or 1 400hps. My screen holes are 1 3/4", and are all filled(added screen about 2 or 3 weeks later then I would of wanted, there flowering abit allready oops), so watchu all think I should do, Idk( about 6 weeks or so left of flower)

Thank much,

oh and if it helps, these are Bubblegum from seed(picking a mom if ones good, have cuts allready) and I use a dayton style 465 cfm blower

 

[yellowbluegreen]

400w, and I would use a parabolic reflector.

 

[Clackamas Coot]

^^^^^^Good advice.

 

[ugmjfarmer]

400 works for my 2x3' area. I use a 19" Cool Tube and never worry about heat, but I have to keep the plants about 4" away to avoid burning

 

[cork144]

soon ill be trying a 250W bent scrog with the screen area of 120cm x 45cm, totals to 6sqft.

2 250s will give you more even light distrabution, where as a 400 obviously has alotta juice and more penatration power

 

[maxpower420]

with a screen in use i would think the light penetration isnt as important seeing you take off everything below the screen anyways. the 250s will run cooler lettin them be closer and with a better coverage with a hundred more watts as well. seems like the better choice to me

 

[etinarcadiaego]

Definitely a 400. I have a 400 and my plants can touch the glass of my reflector without burning. Temps 1" below my light are ambient + 3 degrees.

Also a 400 watt light is more efficient, example:

A 250 Watt EYE HORTILUX Bulb has initial output of 30,500 lumens. So two would output 61,000 lumens and use 500 watts of power (not including power lost @ ballast).

A 400 watt light from the same manufacturer emits 55,000 lumens, and uses 400 watts of power (again not including power lost @ ballast).

Break that down and the 2 (250s) = 122 lumens per watt

Whereas the 1 (400) = 137.5 lumens per watt

So again, I'd go with the 400, and it ain't hard to cool at all if you use an air-cooled reflector. Also, depending on what bulbs/ballast you use, 1 400 watt light (bulb, ballast, reflector) would also probably be cheaper. Using the same example from above, it would be cheaper, as the cost of an additional bulb and reflector (of any kind) would exceed the cost of a single bulb/ballast/reflector.

My $0.02

 

[EvilTwin]

Hi MGT & Peeps,
My vote is for the 400. With a rectangular reflector, you could cover that area nicely at 65 watts/square foot. Going higher in wattage isn't really needed and could actually cause growing complications.
ET

 

[fatigues]

Definitely a 400.

Also a 400 watt light is more efficient, example:

Your analysis ignores that when it gets down to it, lumens as a raw score means absolutely nothing.

What is important is the exposure of the plant to the intensity of the usable light it receives. and as intensity of light fades in proportion to the square of the distance from the light source, that's the mathematical analysis that matters.

And that math does not assist in making a 400w more favourable than 2x250; it does the opposite.

Two sources of light, close to the plants, when measured on an overall basis over the whole breadth of the grow, will generally be more efficient than one source of light, because the distance from the light source for over a third of those plants will be dramatically improved. In order for that not to be true, the single light source must be significantly stronger than the lesser, multiple sources. A 150 watt advantage is not enough to make that "efficiency analysis" work to favour a 400w light over 2x250s over at least a third of the grow.

If you already have the 2x250 lights, and your configuration is 3x2, go for the two 250s you already have. You will end up with a better overall grow and a higher yield without the necessity of having to buy new equipment.

I would note that one 24" cool tube can accommodate two 250 bulbs in a 3x2 setup, if the tube is set up to flow corner to opposite corner.

 

[mrred]

250 v scrog, , 2 250s is to much, seems like a waste, 1 400 would be better, but a 250 vscrog is best,but i'd use the 400 in there, then make a 2x4 box for your 250

 

[BLUNToPOTomuss]

The only thing I would worry about with the 400 and a 3x2 is that that is pushing the outter limits of the 400 foot print.

 

[etinarcadiaego]

Lumens mean nothing, but a 400 watt lamp is still more efficient than 400 watts worth of lesser lamps . . .

 

[Clackamas Coot]

Lumens mean nothing

BINGO!

Thanks for posting that, etinarcadiaego.

Finally!

CC

 

[BLUNToPOTomuss]

Lumens mean nothing, but a 400 watt lamp is still more efficient than 400 watts worth of lesser lamps . . .

BINGO!

Thanks for posting that, etinarcadiaego.

Finally!

CC

how can you guys say lumens dont matter? Its all about lumen output!

Whats the point of having a 150 watt light that only puts out 1200 lumens? The heat that is put out by multiple higher watt lower lumen bulbs makes lumens THE most important number! Hence the reason why HPS' are so much better!

because of the lumen output, not watts. there is a reson why MJ grows so much better under 10k lumens sqft, rather than say 5k lumens sqft.

Because lumens are what REALLY matters. Like Ive said before watts are used more by noob growers bcause it is easier to calculate, but LUMENS are what we are all really after.


Flame away guys! This is my opinion and Im stcking to it!!

 

[etinarcadiaego]

Like Ive said before watts are used more by noob growers bcause it is easier to calculate, but LUMENS are what we are all really after.

HELL YES!

 

[darookie2000]

how can you guys say lumens dont matter? Its all about lumen output!

Whats the point of having a 150 watt light that only puts out 1200 lumens? The heat that is put out by multiple higher watt lower lumen bulbs makes lumens THE most important number! Hence the reason why HPS' are so much better!

because of the lumen output, not watts. there is a reson why MJ grows so much better under 10k lumens sqft, rather than say 5k lumens sqft.

Because lumens are what REALLY matters. Like Ive said before watts are used more by noob growers bcause it is easier to calculate, but LUMENS are what we are all really after.


Flame away guys! This is my opinion and Im stcking to it!!

Lumens are a measure of the visual spectrum that we can see. They are not what we're after. We're after PAR (photosynthetically active radiation), not lumens. Lumens as a relative measure are useful when comparing the same type of light, but the measure lumen is weighted more towards yellow, and less towards red and blue. Plants use light between 400 and 700 nm, which is the PAR range. Here's a little article from sunmaster about the whole thing http://www.sunmastergrowlamps.com/SunmLightandPlants.html.

 

[fatigues]

how can you guys say lumens dont matter? Its all about lumen output!

Flame away guys! This is my opinion and Im stcking to it!!

Because this statement is wrong. Stick to it all you like. Make a T-shirt of it and wear it all day. That doesn't make the statement correct.

It's not about lumen output. It's about lumen reception. The usable light radiation that the plants receive. You can have a 12,000 watt light with a lumen output of close to a million.... if you're an inch away.

But how much of that light is usable radiation, in a given bandwidth, and at what distance from the light source the plants will be when they receive what was once a million lumens (at source) - THAT is the real point that matters when you are talking about "which is better to use".

(A million lumens is a significant advantage where distance is unlikely to come into play in the short run. But 5 or 10k lumens advantage at source? That's not necessarily enough to matter when it is recieved by a plant 3 feet away...when it is compared to a lesser light shining on the same plant from 1 foot away.)

So no - it's not about lumen output. And when you are discussing whether something is more efficient by doing a lumen per watt analysis at source, while ignoring the issue of distance from source when ultimately used by the plant, (in an argument where that fact is the critical issue) then you are just meandering down a trail where you brain is engaged in a long meaningless conversation with Mr. Kush.

(A fun conversation, sure, but not a terribly relevant one.)

 

[mrred]

HELL YES!

after this the 600vs1000hps debate comes in right?

 

[theratings]

I'd go with the 1000w HPS >_>

 

[Clackamas Coot]

how can you guys say lumens dont matter? Its all about lumen output!

Whats the point of having a 150 watt light that only puts out 1200 lumens? The heat that is put out by multiple higher watt lower lumen bulbs makes lumens THE most important number! Hence the reason why HPS' are so much better!

because of the lumen output, not watts. there is a reson why MJ grows so much better under 10k lumens sqft, rather than say 5k lumens sqft.

Because lumens are what REALLY matters. Like Ive said before watts are used more by noob growers bcause it is easier to calculate, but LUMENS are what we are all really after.


Flame away guys! This is my opinion and Im stcking to it!!

Uh huh.

Thanks for sharing!

Peace.

LOL

CC