PARwise

[Nonya]

I've shared PAR comparisons using the Apogee, and spectrum comparisons using the Hopoocolor and UPRtek. They've seen them and have commented.

Wondering why they omitted the fact during my chat this morning that you had already communicated directly with them .

Maybe my PARwise is funky, but I can get a comparison from someone with the device using the same light I have. That, and NIST is 10 miles away. I'll see if anyone I know has anyone there in their network.

Could be informative. As the two spectra you showed in the overlay seemed a bit mismatched, wouldn't a varied selection of single color LEDs be necessary to determine whether the measurements are shifted, or a difference in lux making it appear shifted, or a combination of both to identify the actual amount of wavelength shift? Or would they say who's this dude at the door asking me to check his crappy spectrometer? LOL

If I had to guess, they know it can't match the performance of the Hopoocolor and URPtek. That's ok.

Maybe NIST can help with the Hopoocolor too. They do seem to be slightly evasive: "We need to temper expectation a little too. this is a £220 light meter that can read spectrum which we feel it does exceptionally well! However, it is not an outright spectrometer and doesn’t have the resolution and doesn’t come with accredited lab verifiable calibration standards you might get from such a device."
Another question is whether their "calibration" for the PARwise is consistent across all units. While yours may measure an LED at 470nm, would another PARwise measure it at 465?

What they haven't considered is that the VBR-Aqua, a PAR meter that matches the Apogee 510's performance with a less than 5% deviation, is less than $200 and Amazon allows for free returns. Try the VBR, get your numbers, and tune your light. Then decide if you want to keep the meter.

I don't plan to use it as a PAR meter. I have an SQ-520 which seems adequate. The corals seem to like what I'm giving them, and my budget would preclude buying yet another one. It would be a warm fuzzy if it's found to be close enough.

 

[telegraham]

Wondering why they omitted the fact during my chat this morning that you had already communicated directly with them .

They've commented on posts, then later removed those comments, suggesting that the PARwise isn't all that good at being a spectrometer. I agree, but I also know I'm comparing it to much more expensive devices.

My biggest problem with PARwise is that it underreports PAR. That's a problem, and that's a problem others have experienced. That's a frying your corals problem. To add to the data pool, here's the comparison of the PARwise open air vs the VBR and Apogee. In this case, the Apogee has a slight advantage, in that there is a measurement face elevation difference, but what I'm focused on is how low the PARwise is reading an all sliders at 100% GHL Mitras 7204 running at 45% power and 13.5" above the cabinet. Happy to align sensor face elevations if y'all want to get picky.

163 is quite a bit lower than 200ish.

The VBR does not have a defined immersion multiplier, but I'll share that when I offer in-tank measurements.

 

[Nonya]

I'm only interested in wavelength accuracy between 380 and 500nm. Didn't you say you had a selection of LEDs?

 

[Nonya]

Do you have a plan?

 

[telegraham]

Do you have a plan?

Yes. I intend to continue to show that, without correction multipliers, the PARwise can’t be expected to provide PAR values that align with the hobby’s standard and a device that costs >$100 less. “PAR” is in its name. Its performance should align. Then I’ll get to spectrum.

Regarding alignment, if ITC shares data that shows PAR is being measured accurately when compared to a calibrated instrument, that would be amazing. At that point, they should add a mode in the software that alters the readings to align with an Apogee 510. Then those who have used a 510 to set their lights won’t fry their corals with default PARwise settings.

 

[AKReefing]

I would agree that if they're software-driven they should be able to provide some kind of corrections. I've used a couple of free programs that work with a DIY webcam spectrometer, and one has a calibration function to match peaks to fluorescent bulbs. They work kind of so so, but I'd really like one that's PnP. Maybe there's no money in making a calibration function for the PARwise, but if it can be shown to be unreliable for PAR and/or spectrum, then they'd probably discontinue it.

That said, Any time I've measured my reference set of blue-violet LEDs the measurements are identical each time--down to the nanometer. I wish there was a cheap calibrated light source in that region to use as a reference.

 

[AKReefing]

Hopoocolor advertises +/- 0.5nm accuracy. I'd be interested in how accurate that statement is.

 

[Nonya]

Hopoocolor advertises +/- 0.5nm accuracy. I'd be interested in how accurate that statement is.

Hmm. What standards equivalent would a Chinese manufacturer have that compares to NIST?

 

[Reefering1]

Hmm. What standards equivalent would a Chinese manufacturer have that compares to NIST?

NONE ;-)

 

[Nonya]

NONE ;-)

Now that's an invitation to come full circle. No standards, as in cheap Chinese LEDs?

 

[Reefering1]

Ehh, im kinda bored, kinda drank, I thought it was a little "clever", both are 4 letters and start with a "N"..(?)
So much stuff comes from China, I can't call it trash just because it's Chinese.. but I don't imagine they have equivalent national standards for everything like here(usa)

 

[Reefering1]

Now that's an invitation to come full circle. No standards, as in cheap Chinese LEDs?

 

[AKReefing]

Given BRS' data, I'd like to see the spectrums align better. For me, it's just too far off to be of value, but I'd expect that tuning the result via software could be a thing. If they aligned those peaks, I'd absolutly recommend it for hobbyist use.

But if you just need a PAR meter, this is a better deal - https://a.co/d/6fljHKN

Hmm. Two clear peaks. I'm curious as to what each spectrometer claims are the blue and red peaks. Can you share that? I know the PARwise will only identify the red max.

 

[AKReefing]

That's the point...the spectrums are aligned, but you can see the spectrum misrepresented by the PARwise. Like, still. That's my data captured with my spectrometers, one being the same unit BRS uses, with spectrum values aligned. 380=380, 780=780, and the same for everything in between.

Sorry, I'm still trying to catch up. Can you provide both data graphs separately? I only see one background.

 

[AKReefing]

@telegraham "Given BRS' data, I'd like to see the spectrums align better."

I've searched and can't seem to find the BRS data. Can you point me to it please? Thanks.

 

[telegraham]

@telegraham "Given BRS' data, I'd like to see the spectrums align better."

I've searched and can't seem to find the BRS data. Can you point me to it please? Thanks.

BRS' spectrum data was generated by the UPRtek spectrometer. Any video that showed spectrum...that data.

 

[telegraham]

If you're a PARwise user, multiply ANY of your PAR measurements by 1.26. I’ve compared the PARwise against the VBR-Aqua and Apogee MQ-500 (with immersion applied) at two different points in my tank. That data follows:

Sand
Apogee - 209
VBR-Aqua - 199 (4.75% low)
PARwise - 155 (22% low)

Rock work
Apogee - 243
VBR - 243 (spot-in)
PARwise - 194 (20% low)

Readings were taken with flow off and my ReeFi/GHL Mitras at their typical daytime settings. I made no changes to anything.

The same multiplier applies to the PARwise's plant mode.

 

[AKReefing]

If you're a PARwise user, multiply ANY of your PAR measurements by 1.26. I’ve compared the PARwise against the VBR-Aqua and Apogee MQ-500 (with immersion applied) at two different points in my tank. That data follows:

Sand
Apogee - 209
VBR-Aqua - 199 (4.75% low)
PARwise - 155 (22% low)

Rock work
Apogee - 243
VBR - 243 (spot-in)
PARwise - 194 (20% low)

Readings were taken with flow off and my ReeFi/GHL Mitras at their typical daytime settings. I made no changes to anything.

The same multiplier applies to the PARwise's plant mode.

Good to know. Thanks.
How about wavelength measurements?

 

[Nonya]

Found a comparison via Google search. The PARwise compared favorably to the Hopoocolor, including peak wavelength identification.

 

[AKReefing]

ITC said to me, "there is a lot of concern how he making up those evedences (sic)."

"the graphs look scaled - is it real or is photoshopped? we can see our scale but no reference of the UPRtek one. Both instruments show the peak in number - why did he hide both?"

"And alignment of instruments..."

What are they implying?