Quantum Meter Suggestions

Hey, Y'all. If this has already been covered please just let me know, but I have been searching and haven't found any threads that really cover this.

I want to get some suggestions for a good quantum meter. I have come to realize that measuring PPFD is going to be vital to tuning in my grow and making the most of my light. Since I have the ability to raise and lower my light, as well as the ability to control its output with a dimmer, I have a great deal of control over the amount of light my plants get. In order to evaluate how much light my plants are actually getting and to see how they respond at different light levels, as well as evaluate the evenness of light distribution across the canopy, I need a good effective PAR meter. It seems to me that all serious growers should be using a PAR/quantum meter and is as vital as a pH meter and EC/TDS meter.

That being said, there are a few options out there for quantum meters and I want some guidance about which one to buy. I have seen some good options from Apogee, LI-COR, and Sun System, as well as a lower-priced option from Hydrofarm. I suppose what I really want to know is what is the best bang for the buck. My own budget is going to top out at about $350. However, if you feel the need to weigh in in any way about PAR meters in any way, please feel free.

Also, if @Growmau5, @robincnn, @Greengenes707, or @welight would be so kind as to offer suggestions, that would be excellent.

This is legit
http://www.apogeeinstruments.com/sq-520-smart-quantum-sensor-usb-output/

Need to connect it to a computer tho. But for the price you can't beat it.

BM9AGS said:

This is legit
http://www.apogeeinstruments.com/sq-520-smart-quantum-sensor-usb-output/

Need to connect it to a computer tho. But for the price you can't beat it.

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sound good, we use a spectrometer but that will over $2k for a good one
Cheers
Mark

Apogee makes the sensor for a lot of the more affordable meters anyways so you might as well go for apogee in your budget range.

The new gold sensor are the tits if you can afford it. I like that it is specifically designed to accurately report red & blue wavelengths from led sources.

SQ-120 $155.00 with a DMM is good enough checking ppfd, spread in a tent
SQ-500 $295.00 is what fits the budget if you can hookup a good DMM . I would prefer
SQ-520 $345.00 sounds good but i dont want to have to hookup a laptop/ipad just to get a reading
MQ-500 $495.00 fancy

@BOBBY_G you know any deals on the old Licors ?

Yessss... I definitely had my eyes on the 500 series of Apogee sensors. I even considered the SQ-420, calibrated for electric light sources, but I think the 500 (full spectrum) series is more attractive. @robincnn, the SQ-520 operates as a data-logger if plugged in to a USB power source on its own. This is actually my first choice, although the SQ-500 may be the best, since I do have a multi-meter.

I wonder if the States isn't the best place to buy these. I was quoted at $505 CAD at the end of April for the SQ-520 from Apogee's Canadian reseller. At current rates, the price that you quoted for it, @robincnn, is about $445 CAD.

Oh, and thank you all very much. I know this has helped me make up my mind about which direction I want to go. If it can help someone else find what it is they need, then I will be twice as happy.

atomicData said:

Hey, Y'all. If this has already been covered please just let me know, but I have been searching and haven't found any threads that really cover this.

I want to get some suggestions for a good quantum meter. I have come to realize that measuring PPFD is going to be vital to tuning in my grow and making the most of my light.

Click to expand...

its really not. if you can do some simple math to know how much light youre working with, just get a $20 lux meter to help you smooth out the hotspots and dark spots and you'll do great

real par meters are nice but overkill for 90% of growers

robincnn said:

@BOBBY_G you know any deals on the old Licors ?

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when you say old you mean 'used'? they come up on ebay from time to time, thats where i bought all mine

every setup is simply a sensor + meter

sensors are where the money is. cheapest place ive found to buy a new li-cor LI190R sensor is here (about $450)

they also sell the basic meter LI-250A for $695. kinda spendy for a hopped up multimeter

thats the combo i have but i bought them used off of ebay for ~$350-$400 for both

prior to that i bought a few of these, both included LI190 sensors (if you go this route- make sure the sensor is an li190 or li190r- they are the "quantum" sensors they make all kinds:

http://www.ebay.com/itm/LI-COR-QUANTUM-RADIOMETER-PHOTOMETER-LI-185-/361460502244?hash=item5428b98ee4:g:COEAAOxyrxZRyY3T

http://www.ebay.com/itm/Li-Cor-Quantum-RadioMeter-PhotoMeter-LI-185-Free-Priority-Shipping-/231980833609?hash=item3603229b49:g:dI0AAOSwepJXYhfQ

both run pretty close to my newer digital setup

**but by far the most trick setup comes from our reef brethren (not reefer! ):**

$30 adapter board to work with either an apogee or li-cor sensor to turn a $20 multimeter into a direct reading par meter

how bad ass is that? he didnt market it as li-cor (in fact im pretty sure the only reason it says li-cor on that page is that i asked him about it). I requested assistance and he said:

As for the LiCor, do you have a BNC or bare wire end to the sensor? I wouldn't want to hack the end off of the sensor head, so you may need a BNC male plug so you can bring out two bare wires - I can dig in my connector bin to see if I have any.

You'll also need a resistor, preferably a metal film or precision type in the ~ 100-1000s of ohms range (LiCor sells an adapter with a 604ohm value - I'm not quite sure why they picked 604 but it may be the actual calibration or response curve). The sensor typically outputs 5microamps for every 1000 PAR according to the data sheet - if you have a calibration sheet it may have more exact values.

For the amp, bridge the resistor between the two sensor wires and attach the leads into the Red and Black terminals. Depending on the resistor value, you may not get a 1:1 reading and need to use a different multiplier (for instance the 604ohm would need to be divided by 3 when reading). The amplifier has a fixed 100X gain (so 3mv in becomes 300mv out on the meter, up to 3V max out).

I literally ahvent even had time to decipher what resistor value i need from that but i have a par meter to calibrate it next to. i bought one of the boards- its sitting in my pile of stuff to do. sounds like any resistor in that range is fine and then you calibrate it internally via multiplier

and that is the extent of what i know about par reading - oh other than the fact that they come from the factory matched, calibrated a particular sensor for a particular meter via internal multiplier (or via trimpots i believe in the old analog meters. what i need to do is send my li190+li250a into licor to be calibrated, then i can determine the exact resistor value to make the blueacro board match actual par

Has anybody used the Apogee software? Computers have a lot of advantages, if they are taking advantage of them.

I used to worry about software obsolesence, but virtual machines have the USB thing down.

i think the apogee app looks cool but in my experience dragging a laptop into the garden can be a pain in the butt (my spectrometer is usb)

If you are going to buy a used mv meter, you might just want to buy a good quality used ph meter instead.

I needed one for my hydro system, so instead of buying an overpriced mass-market unit, I bought a lab grade meter off ebay for about $60. Its the tits. Extremely accurate, built like a tank, and I can set it run 24/7 with alarms when it goes out of range high or low. I just buy the $6 probes on alibaba 6 at a time and they last 3-6 months each.

These pro units generally have an mv setting as well and just use the same bnc port as the ph meter. I'm on the lookout now for a quantum sensor.

This is the one I bought a year ago ($1200 when it was sold 15 years ago - not bad for $50). It has an mv resolution of 0.1 mV:

http://www.ebay.com/itm/Beckman-pH-Meter-660-/262519404607?hash=item3d1f60383f:g:ZmAAAOSw91NTthaC




Of course, a lot of these benchtop meters are a pretty good size. Mine has the same footprint as a good size tablet. I suppose someone could pick up a used windows tablet and get a usb sensor as well.

DrBlaze said:

If you are going to buy a used mv meter, you might just want to buy a good quality used ph meter instead.

I needed one for my hydro system, so instead of buying an overpriced mass-market unit, I bought a lab grade meter off ebay for about $60. Its the tits. Extremely accurate, built like a tank, and I can set it run 24/7 with alarms when it goes out of range high or low. I just buy the $6 probes on alibaba 6 at a time and they last 3-6 months each.

These pro units generally have an mv setting as well and just use the same bnc port as the ph meter. I'm on the lookout now for a quantum sensor.

This is the one I bought a year ago ($1200 when it was sold 15 years ago - not bad for $50). It has an mv resolution of 0.1 mV:

http://www.ebay.com/itm/Beckman-pH-Meter-660-/262519404607?hash=item3d1f60383f:g:ZmAAAOSw91NTthaC


View attachment 3733073

Of course, a lot of these benchtop meters are a pretty good size. Mine has the same footprint as a good size tablet. I suppose someone could pick up a used windows tablet and get a usb sensor as well.

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$6 probes are almost cheaper than electrode storage solution. can you throw up a link to good vendor?

gallons of buffer soln (or better yet KCl) make electrodes last a long long time. but i also rinse them with clear water between using them and storing it in solution. or at a minimum a good shake to get the nute soln off

edit: oh nevermind. youre monitoring continuously, thats awesome that you get 6 mos out of a $6 probe!

Actually I meant Aliexpress, which I tend to use for small orders. Its nice to be able to buy instantly, the whole quotation system is a pain in the ass (also you don't get 10 unsolicited emails every time you visit the site). I just pick someone with a good price and high ratings, for instance:

http://www.aliexpress.com/item/New-Arrival-PH-Electrode-Probe-BNC-Connector-for-Aquarium-PH-Controller-Meter-Sensor-gib-Best-Promotion/32316616558.html?spm=2114.01010208.3.214.Bx00dg&ws_ab_test=searchweb201556_7,searchweb201602_2_10057_10056_10037_10055_10049_10017_405_404_407_10058_10032_10040,searchweb201603_1&btsid=ed37fa9d-77d9-4f49-8aa0-f69e1121ed5a

I've had one last over 6 mos, and I've had one last less than 2 months. Most get prob 4-5 months. I use my meter for testing my cichlid tanks as well. They mostly just get really slow at taking measurements as they're becoming worn out,, so when I find it taking a minute or more to get a stable reading I make the switch to a new one.

BOBBY_G said:

every setup is simply a sensor + meter

sensors are where the money is. cheapest place ive found to buy a new li-cor LI190R sensor is here (about $450)


**but by far the most trick setup comes from our reef brethren (not reefer! ):**

$30 adapter board to work with either an apogee or li-cor sensor to turn a $20 multimeter into a direct reading par meter

Click to expand...

Can't like more than once. So I'll quote it too.

It's already my on my x-mas list.
Planning on the diy PVC wand for checking my tanks.

Growmau5 said:

Apogee makes the sensor for a lot of the more affordable meters anyways so you might as well go for apogee in your budget range.

The new gold sensor are the tits if you can afford it. I like that it is specifically designed to accurately report red & blue wavelengths from led sources.

Click to expand...

what model is this that you speak of ? i want one

its the SQ 500/520 MQ-500 mentioned above

In my opinion if i was the op just looking for measurements to get a within 5-10% idea of coverage and ppfd I would buy a cheap lux meter and do the conversion math.