Very different lux readings from two different meters

[PDR]

I just got a Milwaukee MW700 today and it is reading a lot lower lux than the cheap ($20) Amazon lux meter I had previously. I am inclined to go with the Milwaukee readings since it is a higher end unit (well, at least more expense, I assume its higher end). @saltyfilmfolks @mcarroll

Numbers for reference:

Amazon lux meter: 15000 at surface 24" under fixture
Milwaukee lux meter: 8000 at surface 24" under fixture

The fixture is a cheap 48" 4 bulb t5 with 2 ati blue plus and 2 ati coral plus.

 

[reeferfoxx]

I just got a Milwaukee MW700 today and it is reading a lot lower lux than the cheap ($20) Amazon lux meter I had previously. I am inclined to go with the Milwaukee readings since it is a higher end unit (well, at least more expense, I assume its higher end). @saltyfilmfolks @mcarroll

Numbers for reference:

Amazon lux meter: 15000 at surface 24" under fixture
Milwaukee lux meter: 8000 at surface 24" under fixture

The fixture is a cheap 48" 4 bulb t5 with 2 ati blue plus and 2 ati coral plus.

It's dependent on the overall sensor design. Cheap lux meters tend to measure light at a greater degree than some other sensors. I've seen similar lux measurements with a seneye par meter resulting in multiplying the number by 2 gives similar lux readings +/-100. I'm sure Matt or Salty can articulate more.

 

[saltyfilmfolks]

I would go outside and see what you get in a side by side comparitive reading.

Then perhaps hold them and walk to a shade spot. There may be a difference in the response of the sensor as Reeferfoxx mentioned.

 

[PDR]

I would go outside and see what you get in a side by side comparitive reading.

Then perhaps hold them and walk to a shade spot. There may be a difference in the response of the sensor as Reeferfoxx mentioned.

I no longer have the cheap lux meter so I can't directly compare them. I just went outside and in the bright sunlight I got about 95000-110000 lux if I pointed the sensor directly at the sun (I'm on the east coast and these were taken at 4:30pm). If I held the sensor level I would get about half of that. The sun went partially behind the clouds before I could go to the shade. Partial cloud cover was 50000 lux and 10000 in the shade.

Does this sound about right?

 

[saltyfilmfolks]

I no longer have the cheap lux meter so I can't directly compare them. I just went outside and in the bright sunlight I got about 95000-110000 lux if I pointed the sensor directly at the sun (I'm on the east coast and these were taken at 4:30pm). If I held the sensor level I would get about half of that. The sun went partially behind the clouds before I could go to the shade. Partial cloud cover was 50000 lux and 10000 in the shade.

Does this sound about right?

It does. I think I’d trust the new Milwaukee.

Last test. Hold the meter about 8-9 in from the middle of the tubes.

 

[PDR]

It does. I think I’d trust the new Milwaukee.

Last test. Hold the meter about 8-9 in from the middle of the tubes.

18500 max reading at 9 inches from the middle of the 2 center tubes (coral plus and blue plus).

 

[saltyfilmfolks]

Yea that sounds like a cheap fixture. How old are the tubes?

 

[PDR]

Yea that sounds like a cheap fixture. How old are the tubes?

Oh yeah, it is lol. Bulbs are less than 2 months old. What should it be, say with an ati fixture?

 

[saltyfilmfolks]

Oh yeah, it is lol. Bulbs are less than 2 months old. What should it be, say with an ati fixture?

I had a BRS retro kit. It was closer to 26-30,000

 

[saltyfilmfolks]

Here you go.

https://www.reef2reef.com/threads/par-to-lux-conversion-real-world-t5-numbers.281126/#post-3416674