Apogee SQ-420 USB Par Meter

hobbyreefer

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I've rented the Apogee MQ-510 a few times from BRS to measure par. Has anyone used the SQ-420 USB version? Is this an adequate substitute for the 510? The SQ-420 is $234. To me, this might be a better investment vs. renting the 510 for $70.

Does the SQ-420 measure as accurate as the MQ-510?

I have LED and T5 combo.

Thanks!
 
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Miller535

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I've rented the Apogee MQ-510 a few times from BRS to measure par. Has anyone used the SQ-420 USB version? Is this an adequate substitute for the 510? The SQ-420 is $234. To me, this might be a better investment vs. renting the 510 for $70.

Does the SQ-420 measure as accurate as the MQ-510?

I have LED and T5 combo.

Thanks!
I just rented the 510 from BRS. But saw the 420 and was wondering the same thing. The only thing I would add is that if you wanted the handle you get with the rental, it's like $60 also. But something could also be DIY with PVC or something also.
 
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hobbyreefer

hobbyreefer

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Thanks for the response. Yes, I did see the handle was more. I was thinking my arm would make a nice handle ;)

I know it's best to set the lights once and leave everything alone, but I do like to rearrange my aquascape- from time to time and rechecking par would be nice. I've already rented the par meter 3x from BRS. The cost is adding up.

Does anyone know if the 420 is accurate enough?
 

Miller535

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Thanks for the response. Yes, I did see the handle was more. I was thinking my arm would make a nice handle ;)

I know it's best to set the lights once and leave everything alone, but I do like to rearrange my aquascape- from time to time and rechecking par would be nice. I've already rented the par meter 3x from BRS. The cost is adding up.

Does anyone know if the 420 is accurate enough?
I do not know that I firmly believe in the set it and forget it. All lights will still degrade. Like you I like to rearrange once in a while. And what happens when corals start growing big and causing shadows? Or what happens i f I change my pumps out. I think flow affects like penetration.
 

oreo5457

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The SQ-420 sensor has an immersion effect correction factor of 1.08. The
immersion effect correction factor can be automatically applied to SQ-520
measurements by turning on the immersion setting in the settings option of
the ApogeeConnect software, as pictured. Once you are finished making your
underwater measurements simply uncheck the immersion setting in the
software, to turn it off, and continue making measurements in air like normal.
When making underwater measurements, only the sensor and cable can go in
the water. The USB connector is not waterproof and must not get wet.
Further information on underwater measurements and the immersion effect
can be found at http://www.apogeeinstruments.com/underwater-par-
measurements/.
[/URL]
 

chadg

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@oreo5457 , thanks for the info. My main question is really the difference between the SQ-420 and SQ-520 sensors. What are we really missing out on using the SQ-420 vs. the 'full spectrum' SQ-520 with LED lighting? I'm trying to figure out if the SQ-420 will give me 'close enough' PAR readings with LED. I've been told the 420 is really for T5/Halide and the 520 is more for LED. But how big of a difference is there really? If we are talking like a 10-20 PAR miss-read , that is not a big deal as I'm looking for a range.... Anyway, any help on the 420 vs. the 520 for LED's would be greatly apricated!
 

Aardvark1134

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From their page the:
510
389 to 692 nm ± 5 nm (wavelengths where response is greater than 50 % of maximum)

420 and 210
410 to 655 nm (wavelengths where response is greater than 50 % of maximum)

So the 420 is full featured version of the 210 where the 510 is a 420 with better spectrum and accuracy. See pic the blue line is the 510 and the black line is the 210 and 420 and the dotted line is the actual

spectrum.JPG
 
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klimfish

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I have the USB 420 and it was almost exactly the same as the 520 in readings. I rented the more expensive 500 series from BRS before buying the USB 420. Can’t tell a difference.
 
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Reesj

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BRS recently did a Video reguarding PAR. Their concultion was, almost all the PAR meters are very close in numbers.
Even thousands of $ one, give a reading very close to the $200 one. Waste of cash imo and even BRS for spending soo much on high end once..
 

Aardvark1134

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Actually their video showed that 2 of them had errors so serious they removed them from the test and that the seneye only worked for light pointed directly at it not from an angle, and that the 210 over reported yellow light and grossly underreported purple and blue and that the reason its result was close is the underreporting and overreporting almost canceled each other out for overall par on that particular light.
 

ReefLab

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Take a look at the brs video testing them. Honestly, the 510 is not really necessary. The 420 may have an error of +/- 5% but do you care if you have 250 par or 238par in a certain spot? It’s more than accurate enough for our uses.
By the way on the computer app, you select the immersion setting just like on the controller and it automatically applies the correction factor.
 

Aardvark1134

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Look at the actual respose graph from the manufactuer I posted. Its not 5% off. The 420 has the same response as the 210...from 400-450nm it's not even close and thats most of the important range for corals. At 410nm its off by almost 50%
 

Reesj

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Look at the actual respose graph from the manufactuer I posted. Its not 5% off. The 420 has the same response as the 210...from 400-450nm it's not even close and thats most of the important range for corals. At 410nm its off by almost 50%
There are people here reporting with 1st hand experience having multiple PAR meters, saying that they give almost identical readings. Also BRS showing them geting almost exsact readings.
You on the other hand saying they are wrong but to look at a graph ? Dude...
 

xiaoxiy

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There are people here reporting with 1st hand experience having multiple PAR meters, saying that they give almost identical readings. Also BRS showing them geting almost exsact readings.
You on the other hand saying they are wrong but to look at a graph ? Dude...
I'd be interested in seeing how the PAR numbers between the two devices (SQ420 vs MQ510) compare for bluer spectrums or even just the blue channels alone. The manufacturer published data suggests that Aardvark is absolutely correct and the response factor for sub 450nm (royal blue) is 50% or less.

The SQ-420 should be adequate for individuals who run more full-spectrum lights, but I would recommend testing every individual channel (for LEDS) and manually applying the correction if measuring blue spectrums like EcoTech's AB+ or bluer.
 

chadg

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Just watched the full BSR video and looks like the SQ420 (same sensor as the 210 tested) performs 'good enough' for me. I agree with @xiaoxiy that testing should probably be done with only blue then dial in the rest of your colors that you like. That should get you pretty accurate when measuring as it will not be compensating over the full spectrum.

One other question, should you do this in a dark room? Will spill from light in the room really affect the reading? I'll be getting my SQ420 next week. I'll let you know what I find.......
 

leepink23

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Just watched the full BSR video and looks like the SQ420 (same sensor as the 210 tested) performs 'good enough' for me. I agree with @xiaoxiy that testing should probably be done with only blue then dial in the rest of your colors that you like. That should get you pretty accurate when measuring as it will not be compensating over the full spectrum.



One other question, should you do this in a dark room? Will spill from light in the room really affect the reading? I'll be getting my SQ420 next week. I'll let you know what I find.......
Any link to the video? I was searching brs for it and couldn’t find it
 

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