T5 lights and par readings

[saltyfilmfolks]

Oh yea, I assume I have at least 700-800 PAR at the water surface, the Seneye can't be reading it correctly.

All I can figure is it needs distance form the light.
Weird after all the stellar reviews too.

 

[Herby’s reef]

I have really started to doubt mine. I think I am going to try to rent an apogee to test it. It varies every time I check my radions too. Same spots same settings, but par is sometimes very different

 

[jda]

Does the Seneye need the 1.32 immersion factor applied to it? I dunno, just asking.

I have an Apogee 510 and I measured next to a Seneye and it was not even close. The Seneye would get OK readings if we made sure to square it up perfectly, but like even a few degrees to the side and the number would drop significantly. I would trust some of the PAR maps that you see online or the ones from BRS, if they have them. My opinion from the dual test is that Seneye might be OK if you get it perfect, but the Apogee just worked with a pretty large margin for error.

The Apogee 510 is cosine corrected and does have the immersion factor applied already... you literally just put the sensor where you want and read it without much other effort.

 

[Herby’s reef]

Does the Seneye need the 1.32 immersion factor applied to it? I dunno, just asking.

I have an Apogee 510 and I measured next to a Seneye and it was not even close. The Seneye would get OK readings if we made sure to square it up perfectly, but like even a few degrees to the side and the number would drop significantly. I would trust some of the PAR maps that you see online or the ones from BRS, if they have them. My opinion from the dual test is that Seneye might be OK if you get it perfect, but the Apogee just worked with a pretty large margin for error.

The Apogee 510 is cosine corrected and does have the immersion factor applied already... you literally just put the sensor where you want and read it without much other effort.

Thanks! This is the info I have been looking for. I really appreciate it. I have been doubting my seneye for a while but the reviews are so good I had to second guess myself.

 

[dragon99]

I think I figured out why my PAR readings are so low. I won't be able to confirm for a few days because I'm lending the senyeye to a fellow reefer, but I'm fairly confident that this was the issue.

Here's what I found this morning when I brought it to work. Under better lighting, I noticed the lens looked a little dirty.

After a little rubbing with a microfiber cloth....

I peeled off a thin little strip of plastic

I have to believe that partially obscuring the lens was causing the issue. Can't wait to get it back under my lights and see the results.
@Davenkim , check your Seneye and see. I'm wondering if it's a slight mfg'ing defect.

 

[oreo54]

Is that piece "stretchy"?
Looks more like glue or silicone..

Does the Seneye need the 1.32 immersion factor applied to it? I dunno, just asking.

I have an Apogee 510 and I measured next to a Seneye and it was not even close. The Seneye would get OK readings if we made sure to square it up perfectly, but like even a few degrees to the side and the number would drop significantly.

Seneye is not cosine corrected, Apogee 510 is so it'd designed to collect off axis light (think flood vs spot) so yes it's off axis light gathering is mostly non-existant..and no, since it's not designed for air the correction if any is already baked in..

 

[saltyfilmfolks]

Is that piece "stretchy"?
Looks more like glue or silicone..



Seneye is not cosine corrected, Apogee 510 is so it'd designed to collect off axis light (think flood vs spot) so yes it's off axis light gathering is mostly non-existant..and no, since it's not designed for air the correction if any is already baked in..

Makes me wonder how it got such great reviews and did well in side by sides.

 

[Herby’s reef]

I think I figured out why my PAR readings are so low. I won't be able to confirm for a few days because I'm lending the senyeye to a fellow reefer, but I'm fairly confident that this was the issue.

Here's what I found this morning when I brought it to work. Under better lighting, I noticed the lens looked a little dirty.

After a little rubbing with a microfiber cloth....

I peeled off a thin little strip of plastic

I have to believe that partially obscuring the lens was causing the issue. Can't wait to get it back under my lights and see the results.
@Davenkim , check your Seneye and see. I'm wondering if it's a slight mfg'ing defect.

I have looked at the lense before and never noticed anything, but I will look more closely when I get home

Thanks!!

 

[Herby’s reef]

Does the Seneye need the 1.32 immersion factor applied to it? I dunno, just asking.

I have an Apogee 510 and I measured next to a Seneye and it was not even close. The Seneye would get OK readings if we made sure to square it up perfectly, but like even a few degrees to the side and the number would drop significantly. I would trust some of the PAR maps that you see online or the ones from BRS, if they have them. My opinion from the dual test is that Seneye might be OK if you get it perfect, but the Apogee just worked with a pretty large margin for error.

The Apogee 510 is cosine corrected and does have the immersion factor applied already... you literally just put the sensor where you want and read it without much other effort.

I ordered a 510 that will be here in a week, so hopefully I will be able to compair soon!

 

[oreo54]

Well, one factor is the tight beams of LED's.. . Dark rooms w/ zero ambient (usually only a small factor anyways) which is quite off axis..
Last I "heard" was they were working to correct that "issue" ...

As long as you are perpendicular to the light you are OK..

http://answers.seneye.com/en/Seneye...ht_meter_functions/using_the_reef_light_meter

It's a known known..

I've compared it out of water to a good LUX meter and, though it has some issues w/ close distances, it's pretty comparable..

LUX numbers are still wonky but PAR and LUX to PAR conversions w/ the LUX meter are tolerable..

This isn't a scientific instrument and any more than one trick pony device has some issues (till you pay big bucks).

seneye LUX readings make no sense though..
not crazy about Kelvin readings either..

fortunately nobody uses either in sw.. In fw a different story, .

 

[saltyfilmfolks]

Well, one factor is the tight beams of LED's.. . Dark rooms w/ zero ambient (usually only a small factor anyways) which is quite off axis..
Last I "heard" was they were working to correct that "issue" ...

As long as you are perpendicular to the light you are OK..

http://answers.seneye.com/en/Seneye...ht_meter_functions/using_the_reef_light_meter

It's a known known..

I've compared it out of water to a good LUX meter and, though it has some issues w/ close distances, it's pretty comparable..

LUX numbers are still wonky but PAR and LUX to PAR conversions w/ the LUX meter are tolerable..

This isn't a scientific instrument and any more than one trick pony device has some issues (till you pay big bucks).

seneye LUX readings make no sense though..
not crazy about Kelvin readings either..

fortunately nobody uses either in sw.. In fw a different story, .

It’s not the light it’s the meter we’re taking about. (Yea you’ll get less blending etc ) but If it has a limited field of view it will read less of the light esp higher up and closer to the light.
I can almost guarantee the window and the light bulb have zero impact on your par readings. If it does your wearing sunglasses inside.lol.

 

[oreo54]

It’s not the light it’s the meter we’re taking about. (Yea you’ll get less blending etc ) but If it has a limited field of view it will read less of the light esp higher up and closer to the light.
I can almost guarantee the window and the light bulb have zero impact on your par readings. If it does your wearing sunglasses inside.lol.

I know.. point was :

and when I check the par readings I only get 120 at the top.

Same thing I found w/ the seneye and LUX meter.. For whatever reasons if you are around 3-6" (guessitmate from memory) from the light Seneyes read horribly low..
That was for a 30W LED COB...At that distance should have practically pegged the meter (which come to think of it may have happened and the software just threw out garbage)
all I know is reading drastically jumped up w/ distance..and that is w/ a circular cone (120 degrees).
completely opposite of what one would expect..
but, again extreme close distance..


Seems to be optics dependent more than the meter itself..or data overflow..

I have a fw tank which is perp. to south facing windows.. in the N hemisphere..
That matters esp in the winter..
Now not enough to matter for high PAR tanks...
This winter I'll check again..outside and inside the tank.
fortunately the only tank so exposed..

 

[dragon99]

So I ran home at lunch thinking for sure I would get good readings on the T5 now, but alas

ATI 6x54W (3C+,3B+) @ 8in center of fixture, seneye perpendicular to light, about a 10% increase without the occlusion on the lens, but still not what I believe the light to be putting out (more like 700).

Interestingly, if I turn the seneye parallel to the light, it jumps again, so there's definitely something going on with angle of light and distance.

What's even more confusing to me, is that it seems to read an LED just fine, My AI PrimeHD @ 8in

But there's no way that little LED is putting out more PAR than an ATI 6bulb.

Just for giggles I took a reading outside, cloudy sunlight at noon CST

 

[oreo54]

http://www.masa.asn.au/phpBB3/viewtopic.php?f=49&t=220926&start=120
10 bulbs for comparison..

60x33x21 with 10 x 54w PM about 20-25cm above water. fan speed is 6v and 5 bulbs are 2 months old the the other 5 are 7 months. 5B+, 4AB and 1Fiji

another 10 x 54..
http://www.reefcentral.com/forums/showthread.php?t=1641235

 

[Dana Riddle]

Here's a graph of an error you can expect if the Seneye is not exactly perpendicular to the light source. 90 is exactly perpendicular, so just a little off can lend an error of 10% and more.

 

[jda]

^ best graph of the day.

Keep in mind that if you are measuring a 8 bulb T5, then every bulb will be off a bit... the ones on the end moreso than the ones in the middle.

 

[dragon99]

^ best graph of the day.

Keep in mind that if you are measuring a 8 bulb T5, then every bulb will be off a bit... the ones on the end moreso than the ones in the middle.

That's about the only reasonable explanation for why it's measuring so much lower. So it's an adequate PAR meter for LED, but horrible for T5.

 

[jda]

It might also suffer under wide panels like Photon or Atlantik. Under a point source, then you could keep the light pretty much above it at 90 degrees. With a 36 inch panel, some of the diodes will be at quite an angle.

 

[oreo54]

That's about the only reasonable explanation for why it's measuring so much lower. So it's an adequate PAR meter for LED, but horrible for T5.

That's not the reason.. and maybe it's really is that low:

Now here is the REAL funny thing.. Li-Cor had a software error.. Forgot to apply the immersion multiplier.. Believe it was 1.3 which should have been applied to the Li-Cor data but wasn't even when "checked"..
Sooo..multiply Li-Cor by 1.3 for the correct PAr..funny huh..

See BRS for further information..
https://www.reef2reef.com/threads/r...apogee-mq-510-full.292681/page-3#post-3612209

Just an fyi: not under water, not inc. Seneye
https://www.apogeeinstruments.com/content/Comparison-of-Eight-Quantum-Sensor-Models.pdf

 

[Velcro]

So I ran home at lunch thinking for sure I would get good readings on the T5 now, but alas

ATI 6x54W (3C+,3B+) @ 8in center of fixture, seneye perpendicular to light, about a 10% increase without the occlusion on the lens, but still not what I believe the light to be putting out (more like 700).

Interestingly, if I turn the seneye parallel to the light, it jumps again, so there's definitely something going on with angle of light and distance.

What's even more confusing to me, is that it seems to read an LED just fine, My AI PrimeHD @ 8in

But there's no way that little LED is putting out more PAR than an ATI 6bulb.

Just for giggles I took a reading outside, cloudy sunlight at noon CST

That outdoor par seems low. There's a website where you can type in longitude and latitude, as well as a bunch of other parameters to estimate par at that time and date. I find it to be very close to my apogee. Last time I did this it was around 1400 par.

http://clearskycalculator.com/quantumsensor.htm