Yet another par question...

[Steven Postalwait]

I was speaking with a tech from Apogee about the best way to combine readings from different light sources to get an overall par reading. He said theoretically you would take individual readings for each source, then combine them and use the cumulative total. Does anybody have any thoughts on this?

 

[saltyfilmfolks]

Well, they are the authority.

But I’d do it both ways.
Individually and both together.

 

[Steven Postalwait]

Well, they are the authority.

But I’d do it both ways.
Individually and both together.

Yes they are the authority, but “theoretically “ makes me nervous. Maybe I should just quit messing around and get the SQ-520

 

[Sarah24!]

Hello,

What they are meaning by is for example do several tests with the apogee say 10 tests and they all come up with different levels on the sand bed. To get an average from the apogee add all ten up then divide which will give you the accumulative number from that sole device.

Then use like a ly-cor 1500 and do the same thing do ten tests and then divide and see what number you get. Then compare that number to the apogee. I would suggest using a bare min of three testing tools but five would be ideal.

In a test theory it’s extremely important to test each one identically the same way. So the same locations in the tank, the same depth, same settings etc nothing changes. If you do change this, then your experiment can give you false reading s and Info.

Sincerely
Sarah

 

[Velcro]

Yes they are the authority, but “theoretically “ makes me nervous. Maybe I should just quit messing around and get the SQ-520

You should watch the new brs videos on the wwc tanks. They take par readings with both apogee sensors and they are hilariously close.

 

[saltyfilmfolks]

You should watch the new brs videos on the wwc tanks. They take par readings with both apogee sensors and they are hilariously close.

Yup.

 

[Dana Riddle]

I'm confused. Why test individually if a combined measurement is available? Are you trying to measure PAR output of individual LEDs or other light sources? This can be difficult if looking at UV sources, or green LEDs due to the 'green gap.'

 

[Steven Postalwait]

I'm confused. Why test individually if a combined measurement is available? Are you trying to measure PAR output of individual LEDs or other light sources? This can be difficult if looking at UV sources, or green LEDs due to the 'green gap.'

Mainly because I can become a little OCD when it comes to details, especially with numbers. From my understanding the SQ-420 isn’t the best meter for LEDs, so if I can apply different correction factors and combine the numbers my brain won’t let me stop thinking abydoing it that way.

 

[oreo54]

I'll let you in a little secret as far as I know it..
Even the correction factors don''t really work perfectly w/ different T5 bulbs, different lots , different ages..
ALL of it is mostly ballparking anyways.. sooo. don't worry so much.

Every one of these would need a different correction factor due to the spectums and the weaknesses of the meter..
At least as I understand it..

Last, the errors are somewhat meaningless in reality..
Say you measure 500PAR and need to choose between different correction factors of 1.25 or 1.36

625 vs 680 8.8% different, not even worth considering.