Beener

Back to the frustration. While I was light shopping, I asked for a price on a simple little 400W MH set-up. The salesperson asked me if I wanted the price on a 10,000K MH bulb upgrade (which was much cheaper than buying a 10,000k MH bulb anywhere else).

I noted a loss of about 6,000 lumens as compared to a standard MH bulb, and I set out to find an SPD chart. I've been searching for a SPD chart on a 10,000k MH for hours now (any brand of MH)....Nothing.

Does anyone have any info or experience with MH bulbs with this CCT? I realize these bulbs have more blue in it's spectrum, but is it all usable by the plant? If I happen to find a SPD chart in the mean time, I'll post it.

Here's an SPD on the Sunmaster CDX (400W MH). This was another upgrade choice. It looks pretty good, but I have to say, It's a pretty da*n expensive bulb.

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Beener

sientbob

Couldn't have said it better myself.





Here are three different 10,000 Kelvin metal halide bulb spectral power distribution charts.(sorry the multiple one is kinda hard to read) As you can see all three have very different spectral distributions! These bulbs do have good output in the blue region, but they also have a major output in the green region(which is what gives them the higher Kelvin rating and color rendering index).

Hope that helps.

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Beener

Thanks SientBob

Yes that helps...and yes, that doesn't help

Actually, it helps me make a decision. Seeing as the ranges of SPD differentiate so greatly between 10,000k bulbs, I will most likely order the light with the "standard" MH bulb.

That is unless someone can give me a concrete answer on the upgrade bulb brand.

Then if/when I go with a 10,000k bulb, I can purchase one "with" a known SPD. I don't feel good about ordering (and paying xtra for) a bulb that could be a hit or miss....I'd rather pay another $10 and get the best choice. Or for that matter, I'd rather know I didn't overlook a better choice...period.

I'd grab that Sunmaster CDX bulb, except they (meaning everywhere I look) want an avg. of $70 for the 400W!

Penguin had a good point. Throughout my search, I think I'll contact bulb sellers/mfg's that don't offer SPD info, and tell them that without this critical info, I can't purchase their lights at any cost.

I (or anyone else) shouldn't have to spend a third day now, endlessly searching for critical info, just to pick up a simple little 400W MH set-up But...here I go on day three.

Here are a couple of interesting comparison charts I picked up a little while ago. You can see the "huge" difference between the Coralife and HQI 10,000k bulbs.

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Beener

sientbob

those charts are from the same web page I got the multi-graph from.



Right On! just remember, not all "standard" MH bulbs are equal either. They vary even more, from manufacturer to manufacturer. The key is specific data on the bulb in question. Thats why it is so frustrating.

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Beener

I thought that multi chart looked familiar.
I know...it's all a pisser Hopefully, that info will be a little easier to find.

Another pisser here for instance, is the HQI 10,000k bulb. It's a double ended bulb and has no UV filter. So you not only need a tempered glass lense, but you can't use it in a standard Mogul socket. The 400W HQI bulb alone is about $90!

This BS is enough to make me spark up an early buzz...No S***, it's really pissin' me off. I would take the "up-sell" if I just knew what it was they're trying to sell me! All I freakin' want is the best bang for my buck....If it means spending a bit more, then so be it. That doesn't mean a $200 upgrade on a $130 set-up though

I'll gladly do the homework... but wtf, It's dam* near impossible to find the study resources.

I even checked out the Hortilux Blue bulb. The 400W bulb is about $80/90 bucks, and comes in at 29,000 lumens. It has a good amount of usable light spectrum, but at what point does the loss of lumens finally play a part.

You could literally spend a couple of days doing the math on different bulbs, before you even had a clue as to what you're dealing with.

Perhaps the loss of lumens on the Hortilux Blue bulb means nothing, when considering the actual amount of usable light output.

OK that did it ...I think I need to burn one up and relax for a couple minutes

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Beener

sientbob

Forget about LUMENS!






edit:
A Rational Approach to Light Measurements in Plant Ecology

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Beener

You're absolutely right bro'...That's become more & more obvious. You can have balls out lumens, but if they aren't where they need to be...it's pointless, wasted electricity (& heat).

There, that's better. Burn a nug...talk a bit. Now I'm back to that great deal I found in the first place. All new, complete 400W MH, delivered to the door for $130.00....that's cheap and easy. Fugg the no name bulb upgrade.

I priced the "Super Actinic R" bulb that Penguin posted, and it's an inexpensive (tube) bulb. Dollar for dollar, using a few as supplemental lighting is probably much more cost affective, and they appear as if they would add an excellent blue punch to a good MH.

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Beener

penguin

How many stoners does it take to install a light bulb?

Given the available data it's impossible to say whether the HQI 10K is more efficient for plant growth than the "standard" MH (whatever that is). Among the lamps compared for PPFD (nifty graph BTW), it obviously has the highest radiant efficiency and has a pretty good spectrum. The UV could be useful in a flowering room.

Considered along with other data, lumen ratings can be useful information.
Given two lamps with similar PAR efficiency, but differing luminous efficiency, the increased luminous efficiency must come at a cost to plant growth radiant efficiency. In this case we want the lamp with lower lumen output.

The HQI does put out a big % of PPFD in the 490-590nm range (photopic curve peaks @ 555.15nm) and therefore should have fairly high (= bad) luminous efficiency. Unless the "standard" MH is optimized for luminous efficiency, the difference of 6000 lumens suggests that the HQI 10K has a lower radiant efficiency. But without some kind of spectral analysis of the "standard" MH, we still don't have enough info to make a choice.

Assuming that the HQI does have better plant growth radiant efficiency, the real question is whether that's enough to justify the high initial and operating costs of using the HQI lamp. This I kind of doubt.

[edit]The thing that tweaks me is that lamp manufactures start out with spectroradiometer data - the useful information - and then mangle it into useless photopic ratings. [/edit]


penguin

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sientbob

Did we decide which one to buy? muwhahaahahahahahahahahahahaha




Right, so what is it we are after? Total PAR, which is all the light between 400 and 700 nanometers, and then take a look at the SPD graph and try to guage its effectiveness at stimulateing the photomorphgenic responses we are after at any certain time during the grow.

Aren't those the two most important considerations we need to look at?

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Please read our Posting Guidlines, Grow Guide, and Library of useful threads.
Learn about light? Which lamp to buy? Troubleshooting HID and Fluorescent lamps
Atomospheric Control guide. Fun with ventilation. Fan speed control
Latitude model. Outdoor grow started from cuttings. Adventures in growing Outside.

lilbud99

Penguin, Beener2969

Thanks for the links guys, some very interesting reading, it'll take me a while to digest it but its all there. see you in about a month!!!!!!!!

Im currently using a GROLUX full spectrum lamp which seems to be quite good, but im always eager to learn of new and improved systems. HEY, if it helps get more BUD im all for it!!!!!!!!!!

Lilbud (wants bigbuds)

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