Good PAR meter for reasonable price?

[Loc Dog]

I have another LED grow that I screwed up from too much light. I want to maximize these lights for most grams per watt. Heard lumen meter will not do that, so going to bite the bulet, and buy a PAR meter.

Any suggestions on a very good meter, for the least money? I found one for about $160, which is $200 less than the average price. The one I am looking at is Photobio brand.

Anyone have ones they like or hate, and reasons why?

 

[Switcher56]

The one I use. I am not a lab... I do not need 0.000000006 accuracy. It does the job for $150 (was).

Inches away and the heat felt on the back of your hand = ball park figures!

 

[Ibechillin]

Ive been following some threads with people using the Pulse Pro system, not sure how accurate the PAR/spectrum analysis is compared to the more specialized brands but I like the price for amount of features.

 

[f-e]

Limitations in the sensors available to manufacturers make these very expensive toys when it comes to our use.

The typical sensor measures to 650nm then falls off a cliff. By the 660nm point we want to produce, they are down to about 20% effective. This isn't a reading you can take then simply times by 5. Manufacturing tolerances won't allow it in mass production. Each sensor would need individually testing, or the meter individually calibrating. A level of perfection that would rely on all our leds not having the tolerances they do. You just can't calculate the truth. If you want to do that, use a lux meter and a calculator. You can't measure 660nm without an additional sensor aimed at that purpose.

Muddying the waters further, we have the Emmerson effect. Many of our lights have 730nm emitters as they support the 660nm functions greatly. A par meter doesn't see that as par light.

The par meter is good with the sun. We know the suns output. It can do a check on white balance and then it knows for sure whats happening between 650nm and 700nm, unless the sun broke. The gist here is that the meter can't reliably see past 650nm and so must make it up with math, which means it must understand the light source.

You can visit the big brand site. All the meters are listed individually, with the math to make the meters reading closer to the truth when leds are used, not the sun. We know that not all leds are equal though. Whats going on below 660 isn't a good reflection of what happening above 650 where we actually do our work.

In short, they are little closer to the truth than a $10 meter. Neither meter is much use if you don't know your plants. They just help get even canopy coverage if you don't know what your plants like. If you want a ballpark figure for the average plant, then the accuracy of a lux meter is extremely good as a starting point.


If anybodies 'really' following this, then ponder the white balance check. The meter will be looking at red and blue. It won't see our red much. If it see's the blue, it will think the light very cold. With that in mind, it will presume the light above 650nm is very low. So when it does it's calculation of what's happening above 650 it's actually heading in the wrong direction. Thinking there is little going on, in the area it's all going on.


I use this, the cheapest thing I could find. Though not from Amazon, the sellers there have to charge 50% more to cover Amazon taking a third
https://www.amazon.com/Leaton-Digit...1613203406&refinements=p_72:2661621011&sr=8-6
It might say 4% accuracy, but what if it did it's worst and said 570ppdf at 600ppfd? You can't copy someone else's grow anyway. It's only a ballpark figure. High accuracy isn't helpful. Our grows are not identical.


In closing.. I would sleep better at night knowing I had a meter that said ppfd in the corner. I would. It's true. I could even buy some big glasses to put on when I use it. White coat maybe. Over-shoes. The possibilities are endless. People would be peering over my shoulders, looking between my meter and theirs, as they slid theirs in their pockets. I want one right now lol





Edit:
Here are the correction factors for apogee meters. You can see a worst case scenario of a 55.8% difference between the display and the truth with some lighting. Which is pretty much ours, though ours would be worse still if they actually included 730nm
https://www.apogeeinstruments.com/how-to-correct-for-spectral-errors-of-popular-light-sources/

Edit2: So looking it over, we have over a 50% discrepancy at 667nm (our red) and a 100% discrepancy at 730nm. Blue just 12% out, while green just 7% out.
The argument against lux meters is that they see green and work out the rest. It's a weak argument. Muted you might say.


A third edit..
Most lux meters are not going to look at green. It's unnecessary expense. They will just look at the signal from the light capture device (an ldr) as a total. If you spend a bit more, then green filters may be employed to address the effect of light balance a little. If you spend quite a bit, some meters look at the red content. As red is attenuated less by seasonal changes. Each step of expendature makes the meter worse for our needs. We actually want the $10 meter so that we know what we are getting. In order to exchange notes.

 

[Loc Dog]

I am going to have to get something. I will be dead before I do enough runs to tune it in properly with some way to measure the light intensity at tops. I have already ruined 3 months worth of work. Now confused if I should just get a cheap one, and use for ball parking, or buy an apogee which is calibrated against a reference light, but costs 3 times as much. Might just go back to HID.

These were the ones I found for reasonable price, and more expensive one claims to do up to 700nm. I was told 720nm was only needed for signalling, and used 15 minutes after lights come on and 15 minutes before lights go off. I will have to see how much Vero 29;s have at that range.

Found one from Photobio for $160 and one that sounds a little better for $190 from Lifees. Anybody have experience with these?

 

[f-e]

If it doesn't tell you what it claims is going on to 700nm then it's not a par meter. That doesn't mean it can see 700 though. It just knows what is there from looking elsewhere and thinking it's the sun, or some other source it's calibrated to. However, not LED.

The $10 meter has been calibrated against led. A specific blend we actually use.

 

[weedobix]

The first time I used LEDs I did the same, I don't use them without dimmers and a wattage meter plug now.

I looked at par meters too but it was like £500 for an apogee. There are some phone apps which can turn your phone into a meter.
In the end I just got used to the distance and power needed in the different stages of growth.

 

[Loc Dog]

The first time I used LEDs I did the same, I don't use them without dimmers and a wattage meter plug now.

I looked at par meters too but it was like £500 for an apogee. There are some phone apps which can turn your phone into a meter.
In the end I just got used to the distance and power needed in the different stages of growth.

Those are lux meters that just try to assume the correct PAR equivalent.

They (apogee) sells a sensor that attaches to Iphone for about $230, that does PAR.

 

[Loc Dog]

If it doesn't tell you what it claims is going on to 700nm then it's not a par meter. That doesn't mean it can see 700 though. It just knows what is there from looking elsewhere and thinking it's the sun, or some other source it's calibrated to. However, not LED.

The $10 meter has been calibrated against led. A specific blend we actually use.

Any idea what light factor for lux to par calculator should be used for vero 29 gen 7's 3500K? If so I will search my garage. I know there is one buried in there somewhere.

 

[Switcher56]

Those are lux meters that just try to assume the correct PAR equivalent.

They (apogee) sells a sensor that attaches to Iphone for about $230, that does PAR.

... IMHO a phone is a phone! A gadget attached to it doesn't make it a PAR meter.

 

[Switcher56]

When we look at what we are measuring, how accurate does one need to be, considering the light intensity in the following circumstances:

• seedlings ~ 60-90 umol;
• clones ~ 100-200 umol;
• veg ~ 300-425 umol; and
• bloom 700-1200 umol.

What we/you are looking for is repeatability. To the point that because I have used mine from the beginning, I play a guessing game wrt what is the PAR reading at a certain distance, and after a while you have a good idea of what height should your light be at to meet those goals.

I use mine for tent management, as I grow more than one strain at a time, and what the meter tells me at various spots in the tent. If a plant doesn't agree with the amount of sunshine for the lack of a better word, I simply more her to a cooler part of the tent (where the light is not as intense (shade, sort of)).

It's a tool, nothing more. Does one need a $200 saw to cut a 2x4 or will a $50 one cut the 2x4. Repeatability, is what you seek vs accuracy at the other ranges of certain measured spectrum. The meter might detect UVA and UVB but it doesn't tell you that unless you are going to buy an expensive one, and yeah... catching$$ look at spending over $1k for that information. If it just a tool to help figure out what distance to place your light, the rest becomes a moot point.

Shane uses one that can suck the chrome of a bumper hitch... https://www.youtube.com/channel/UCSZwj4zGhH1yklVFxS54qdA

He needs one like that for what he does, we don't!

 

[Loc Dog]

A smartphone is basically a computer, with telecommunications ability. Apogee sells several usb connected sensors (for over $200) that can connect to computer or phone running the appropriate software. Saves the cost and redundancy of a microprocessor device to view output.

I am going to try using LUX meter and use a conversion calculator, and see how that does for positioning lights. If I was going to go PAR meter, and had a smartphone would just buy that sensor and save $200 to $300, but I have a $40 flip phone, which can not do anything.

 

[Switcher56]

... whatever floats your boat

 

[f-e]

700 - 1200 is bright too fucking bright. 700 is going to be too much for any newbie. I would target 500 - 600 which will still put 18 in a meter. Going for gold on your first run will just lead to a fall. Though some sats will suck it up.

The conversion from lux to ppfd might be about 65 but there is little point making the conversion. Just use it as is. 30,000 should be satisfactory for a first run. Enough to grow reasonable bud without lots of stress. 40,000 is very nice. 60,000 is shooting for gold.

It's all in the pic I posted. No point me saying it a third time

 

[Fitzera]

Dots put me onto the cheap lux meter Migro talked about in one of his videos. He linked the video in my thread. About $30cad and 2 days shipping. It definitely reads different than the app on my phone, although my phone wasn't too far off, but off enough. Migro talks about it being pretty accurate, tested against his apogee I think. It's good enough for me!
AP-881E

The only thing I'm not 100% sure about is the conversion factor to use. My light has both 3000k and 5000k as well as the reds. Conversion factors migro gives are for 3000k, 4000k 5000k etc...I went with 4000k as an average...which may be the wrong way to look at it.

 

[Switcher56]

700 - 1200 is bright too fucking bright. 700 is going to be too much for any newbie. I would target 500 - 600 which will still put 18 in a meter. Going for gold on your first run will just lead to a fall. Though some sats will suck it up.

The conversion from lux to ppfd might be about 65 but there is little point making the conversion. Just use it as is. 30,000 should be satisfactory for a first run. Enough to grow reasonable bud without lots of stress. 40,000 is very nice. 60,000 is shooting for gold.

It's all in the pic I posted. No point me saying it a third time

I didn't invent those numbers! I didn't forget that CO2 augmentation is necessary over 1000 umols. I run my light at 850-900 in bloom.

 

[Loc Dog]

700 - 1200 is bright too fucking bright. 700 is going to be too much for any newbie. I would target 500 - 600 which will still put 18 in a meter. Going for gold on your first run will just lead to a fall. Though some sats will suck it up.

The conversion from lux to ppfd might be about 65 but there is little point making the conversion. Just use it as is. 30,000 should be satisfactory for a first run. Enough to grow reasonable bud without lots of stress. 40,000 is very nice. 60,000 is shooting for gold.

It's all in the pic I posted. No point me saying it a third time

I just checked with an old lumen meter and get 30000 to 45000 at bud level with lights turned all the way up. Wondering now why leaves are bleached, unless damage from first few days it was setup and they were lower. Will check in GG4 group if it is known to have problems with strong light.

 

[Muleskinner]

700 - 1200 is bright too fucking bright. 700 is going to be too much for any newbie. I would target 500 - 600 which will still put 18 in a meter.

Interesting, I'm starting to notice the same thing. I'm not sure there's much benefit to going above 600 umol/m2 unless you're using CO2 and/or chemical or hydro nutes. I've seen graphs showing a plateau in yield over 500 or 600 without added CO2. Especially with horticultural LED's which focus most of the light on red & blue compared to HID. Also tents with reflective walls will need less than open greenhouses. I'm not sure organic soil plants can keep up with super high light levels.

I recently sucked up the $500 for the Apogee meter. It seems high but is actually not much compaired what I've spent on LED fixtures. I got tired of burning the plants as I moved them between veg & flower or different tents. Holding out the back of my hand turned out to be massively inaccurate! Very happy w/ the meter. Light shock can cause plants to look either hungry (yellowing leaves) or burnt (curling downward) and cause you to adjust nutes and create more problems.

If your lights have different spectrums or you're moving plants between LED and HID it's even harder to tell how much PAR they're getting without the meter. It can take 2 or 3 weeks to slowly adjust the plants from a dimmer veg area to the full brightness of flowering.

 

[flylowgethigh]

I am going to have to get something. I will be dead before I do enough runs to tune it in properly with some way to measure the light intensity at tops. I have already ruined 3 months worth of work. Now confused if I should just get a cheap one, and use for ball parking, or buy an apogee which is calibrated against a reference light, but costs 3 times as much. Might just go back to HID.

These were the ones I found for reasonable price, and more expensive one claims to do up to 700nm. I was told 720nm was only needed for signalling, and used 15 minutes after lights come on and 15 minutes before lights go off. I will have to see how much Vero 29;s have at that range.

Found one from Photobio for $160 and one that sounds a little better for $190 from Lifees. Anybody have experience with these?

My little $150 Photobio is my main tool. I really like it, and have no idea how to set a light without it. There is a short coiled cord, and a longer one that you can use as a remote. Look at the post I made in the LED section, see it in use.

For example, I have the lights at the nursery at 250 umols at plant top - and they are not stretching between nodes, the stalk is no longer getting too long. This is on the 3rd set of leafs. That may even be too much light.

Edit: after I typed I went back and saw Switcher's post. I agree, 240 may be too high for my plants right now. The light meter is my main tool. EC truncheon - don't need it. Ph , naw. The Co2 logger is also nice. BTW, there is a CO2 chart better than this one, but this is the general idea. Temperature also is a factor, and I bet humidity as well.

 

[troutman]

This website may help.

Lighting Radiation Conversion