PAR meter recommendations...

[firefiend]

So, I'm looking to buy a PAR meter and hope that I can I find a solid one for around $300.

So if any of you have one, have purchased one or have experience with them your insight would be greatly appreciated.

Thanks, all.

[Hoppy]

Look for the Apogee Quantum 200, which I believe is the one most commonly used. And, it works great.

[Naekuh]

+1 also looking for a cheap PAR meter.

Originally Posted by Hoppy

Look for the Apogee Quantum 200, which I believe is the one most commonly used. And, it works great.

Hoppy the SQ series OK?

Model SQ $139.00

Is the multi channel recommended?

[Hoppy]

Isn't the SQ series just the light sensor, so that you need a very good milivoltmeter to read it out?

[Naekuh]

Originally Posted by Hoppy

Isn't the SQ series just the light sensor, so that you need a very good milivoltmeter to read it out?

Meh reading vendors site its says your right..

you need the MQ's ...

those are 300 dollars as the ops says...

I was hoping there were something a bit cheaper...

[DKRST]

Just got my MQ 200 about two weeks ago. Under $300, free shipping, shop around the net and wait for a sale, but still not much below $300. I think mine was $289 or so. Easy to use, auto shut off. I purchased to do some research projects at work. If you get this one and plan on using it a lot (for the local aquarium club, etc), I recommend buying the telescoping "arm" to help take measurements. I made an arm by twisting some 10 gauge copper wire (w/power drill). Works pretty well, but not quite rigid enough and hard to store @ 3' long!

[dundadundun]

Originally Posted by Hoppy

Isn't the SQ series just the light sensor, so that you need a very good milivoltmeter to read it out?

let me get this right. the sensor reads @ 5umols per mV, so a multimeter that's capable of reading @ .1mv should give me accuracy of .5umols +/-(?)%, correct?

i mean is there some noise/variance that may change too fast for a multimeter readout to capture and display whereas a graphing meter would be necessary for even remote accuracy? or would it be pretty straight forward, plug and play as long as i could get it connected to a multimeter capable of 0.1mV readouts to give me a somewhat accurate readout @ .5umol increments?

if there's not something i'm missing, this may just be the "affordable" answer for the budget aware handy man with limited need and more limited access.

here's the conversion quotes from the online manual for the SQ series for reference...

All Apogee quantum sensor models have a standard calibration of exactly:
5.00 μmol m-2 s-1 per mV

their worked example...

sensor output * conversion factor = PPF
400 mV * 5.00 μmol m-2 s-1 per mV = 2,000 μmol m-2 s-1

i've got a multimeter or two lying around that are capable of such readings. even if not, there's always the possibility of picking one up. pretty sure i could get something in the $60 - $80 range... or is there a reason that may not be advisable when considering it's use in conjunction with the sensor? the meter certainly would get more use than the sensor in my house, that's for sure.

if there is any likely downside that you can think of, by all means let me know.

[Daximus]

Originally Posted by Naekuh

Meh reading vendors site its says your right..

For the record...Hoppy is pretty much always right, lol

[Naekuh]

Originally Posted by Daximus

For the record...Hoppy is pretty much always right, lol

lulz... i agree... hoppy is typically correct..

[Hoppy]

Originally Posted by Naekuh

lulz... i agree... hoppy is typically correct..

I'm just good at hiding my mistakes.

[DKRST]

Only question I'd have is regarding the sensor being well-sealed against water, both the sensor and the sensor cable connection (and I have not looked at the sensor specs, so this is idle speculation). Other than that, it's certainly cost-effective!

[Hoppy]

It's the same sensor, which is very waterproof.

[dundadundun]

que no gusto? Lo siento.

hoping to hear back from apogee about my questions some time this week.

[dundadundun]

my inquiry...

To: tech support
Subject: sq sensor inquiry



from what i gather from the spec pages on these units, they can be used in conjunction with a decent multimeter.

my question would have to do with accuracy and difficulties associated with use in such a manner. i am curious as to whether a digital readout would be sufficient on a multimeter that reads at a minimum of 100 microvolts (.1 millivolt).

my concerns would be along the lines of whether the reading would be one such that would be rapidly changing so as to cause difficulty in relaying that information and displaying it in real time on a digital display of a multimeter.

another concern would be that in the case, the display would be sufficient... how would my accuracy be affected with a .1 millivolt capable multimeter vs. the purchase of a whole unit. say an MQ-200 for example.

now, from what i gather from the online manual, there is 3 wires on the sensor. of course my multimeter only has 2 usable prongs (+ and -). this leaves the question of whether or not the ground lead is necessary when used with a multimeter and if it can just be connected with the negative lead to facilitate a measurement.

from what i understand, the sensors calibration is set to 5.00 μmol m-2 s-1 per mV. my meter displays down to .1mV. i assume that gives me the possibility for a measurement down to 0.5 μmol m-2 s-1 per each 100 µV. would this be correct?

if there are any other complications, difficulties or work-arounds that may be necessary, please graciously inform me. i'm very interested in this product (SQ-120), yet feel it would be a waste to go as far as purchasing an MQ model given the relatively infrequent use that will be necessary for my purposes.

thank you very much for your time and patience with my thick skull,
signature

the response...

my name,



A multimeter will work just fine for your application. The ground wire should be connected with the negative lead as you stated. Yes the accuracy is 0.5 μmol m-2 s-1 per each 100 µV.



Let me know if you have any other questions.



Skiffington Smith
Electrical Engineering Intern

so if you have a multimeter that can read .1mV than you can have an accuracy of .5 μmol using just the SQ-120 sensor for your tanks.

with a little searching, there shouldn't be a problem getting a multimeter capable of such measurements for under $80 if you don't already have one.

[Optix]

^please start a thread if you go this route

some simple math could mean $100 savings