Par meter and ppfd questions

linky

linky

Well-Known Member
CobKits said:
even your buddy growmau5 uses a $30 light meter to balance out his garden

plant response will tell you a lot more than a deadly accurate meter about what your plants like, but you can go to teh best part of your garden, with any meter, and take a reading, in order to replicate that throughout the garden. its all relative (assuming same spectrum/light type throughout garden)
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Yeah, I understand that and I agree.. I just wanted a nice toy that would give pretty accurate numbers, I think I will order the apogee 500 meter they have for 500 bucks.
 
1KTrees

1KTrees

Member
BuddyColas

BuddyColas

Well-Known Member
linky said:
Yeah, I understand that and I agree.. I just wanted a nice toy that would give pretty accurate numbers, I think I will order the apogee 500 meter they have for 500 bucks.
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So what K and CRI cobs are you trying to measure?
 
linky

linky

Well-Known Member
BuddyColas said:
So what K and CRI cobs are you trying to measure?
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looking to measure the gavitas, cmh 630 watt de fixtures, cree 3590 fixtures and vero 29 fixtures. crees are 3500k 80 cri and veros are 3000k mostly 80 cri and some 90 cri now. Ordered parts to build 2 more of these lights in this thread, ordered black 8020 this time though :). I went with 5 3000k 80 cri and 5 90 cri instead of 6 and 4 this time.
 
BuddyColas

BuddyColas

Well-Known Member
linky said:
looking to measure the gavitas, cmh 630 watt de fixtures, cree 3590 fixtures and vero 29 fixtures. crees are 3500k 80 cri and veros are 3000k mostly 80 cri and some 90 cri now. Ordered parts to build 2 more of these lights in this thread, ordered black 8020 this time though :). I went with 5 3000k 80 cri and 5 90 cri instead of 6 and 4 this time.
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Quite a variety. Interestingly I looked at the 3000/90 curve on the Cititzen 1212 on Cobkits site. It is interesting to me to count all the squares below 660nm, then count all the squares above 660nm which are not counted with the 120. Now admittedly this is not exact, but it looks to me like at least 20% of the total photons are not counted. So your 650 umols is really significantly higher. I hope Apogee comes through with some accurate multipliers for the warm cobs. I'll be watching your thread!
 
linky

linky

Well-Known Member
Apogee replied, this is what they said

Thanks for the email. It is hard to know for sure what the errors would be with your specific light without the spectral curve of your light in spreadsheet format with the intensity at each wavelength. If we had this information we could calculate the theoretical spectral errors of our sensor to your lights. What we can offer you is the following links based off of the lights we have calculated the SQ-120 errors on.

http://www.apogeeinstruments.com/quantum/?wvideo=ilzactjeqj
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BuddyColas

BuddyColas

Well-Known Member
linky said:
Apogee replied, this is what they said
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There are guys here who can generate, a "spectral curve of your light in spreadsheet format with the intensity at each wavelength." But I'm not one of them.

Check out this thread:
https://www.rollitup.org/t/cob-efficiency-spreadsheets.865238/page-3
You could PM Alesh...he is one of the guys who can generate the spectral curves in spreadsheet format. Or he might tell you who to talk to. Just don't pitch your 120 just yet.
 
KonopCh

KonopCh

Well-Known Member
I bought LUX meter... I don't have money for PAR meter. Anyway, how much lux is good for seedling, veg and flower?

Can you compare PAR and LUX readings please? Max 900-950 umols here.
 
wietefras

wietefras

Well-Known Member
There is a thread here which lists several conversion factors. Look up the lux to par conversion factor for the specific spectral distribution of your light.

Or in general, for 3000K 80 CRI COBs it will be somewhere around 67 to 69 and for 3000K 90 CRI around 57. Divide the lux by that factor and you get PAR.
 
KonopCh

KonopCh

Well-Known Member
wietefras said:
There is a thread here which lists several conversion factors. Look up the lux to par conversion factor for the specific spectral distribution of your light.

Or in general, for 3000K 80 CRI COBs it will be somewhere around 67 to 69 and for 3000K 90 CRI around 57. Divide the lux by that factor and you get PAR.
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Okay, thanks!
But another question is... what's optimal? For seedling, for veg, for flower How much PAR? For flower I think 900-1100 is max without CO2, right? What about veg?
 
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