Lux meter- am I doing it right?

DracoKat · Aug 8, 2016

I'll try tomorrow. it's night now, lol.

maybe I am just doing it too close to the fixture. Next time I have someone come by, I'll ask them to hold the fixture for me to get a proper reading

dragon99 · Aug 8, 2016

First thanks for the info salty. I've read through this and another thread where you've been patiently explaining this.

So angling the sensor for the highest reading is the correct thing? I seem to get more consistent readings with the phone parallel.

I've been measuring my AI Prime's and Prime HD. I get ~25-30K from the Primes and up to 45k from the HD. It always in a very tight spot that I get that high of a reading with my phone angled.
That's with the units running 20k color at 100%. They are spaced about 10-12" apart with the HD in the center.

That's measured with my Moto X phone (which has a light sensor, not using camera) on the Lux Meter app. I have an old Samsung S4 that reads in the 100's to 1000's. I'm on a wait list to borrow the club's PAR meter so hopefully I can get some confirmation soon.

saltyfilmfolks · Aug 8, 2016

dragon99 said:
First thanks for the info salty. I've read through this and another thread where you've been patiently explaining this.

So angling the sensor for the highest reading is the correct thing? I seem to get more consistent readings with the phone parallel.

I've been measuring my AI Prime's and Prime HD. I get ~25-30K from the Primes and up to 45k from the HD. It always in a very tight spot that I get that high of a reading with my phone angled.
That's with the units running 20k color at 100%. They are spaced about 10-12" apart with the HD in the center.

That's measured with my Moto X phone (which has a light sensor, not using camera) on the Lux Meter app. I have an old Samsung S4 that reads in the 100's to 1000's. I'm on a wait list to borrow the club's PAR meter so hopefully I can get some confirmation soon.

Glad I could help.
Fwiw phones do not work the same as a light meter. Tech reasons It usually leads to some confusion. I got the 15 dollar red lux meter on Amazon. It's much more accurate by nature. And honestly I'd bet you won't regret the purchase. For acclimation settings resets. Color changes.

dragon99 · Aug 8, 2016

That beats 200 for a seneye. It's probably worth it to see if the app is wacky.

saltyfilmfolks · Aug 9, 2016

Yea It's just inconsistent.

dragon99 · Aug 11, 2016

So with a meter now, I'm seeing 28,000 under the PrimeHD, and 19,000 under the Primes (16k temp setting which is about what I'm running). Reading 9.5" under the lights, dead center. (Get 39,000/32,000 at full on)
So I'm getting 280-400Par at the waterline, right?

For my acro's and monti's that are 8-11" under water is that enough PAR?
What about for deresa sitting on the sand @ 18"

saltyfilmfolks · Aug 12, 2016

dragon99 said:
So with a meter now, I'm seeing 28,000 under the PrimeHD, and 19,000 under the Primes (16k temp setting which is about what I'm running). Reading 9.5" under the lights, dead center. (Get 39,000/32,000 at full on)
So I'm getting 280-400Par at the waterline, right?

For my acro's and monti's that are 8-11" under water is that enough PAR?
What about for deresa sitting on the sand @ 18"

Call it 35000 and best case it at 50(sun)
700par.
28000 at 50 is 560.
Run the same lux numbers at 45(t5) and 60(common led). And it gives an average.
So if it's 500 yea probably if the clam is around 200 par or so. IMO.

Now it gets tricky

some studies say 450 par is fine and corals don't need much more than that (D riddle. ) he also says that corals (the zooid actually) are very tolerant of changes to lower light to a certain point. Thus many folks success with in adequate light and IMO the myth of softies being low light.

My take away has now been that now you know your range of lux and par if the animal starts to brown (high nutrients low metabolism due to low light) you know you can increase the intensity and know almost exactly how much. I.e. 100 par is 1000 lux.

(@50)
It is exactly the same as adjusting the amount of No Po or alk in the tank for a specific coral type

i.e. Zoas and dirty water.

Further if you increase the light the coral increase nutrient intake lowering available no and Po and depleting alk. So I used this therum to rehab a tank that had high Po bound to the rock and was a cyano disaster.
I out competed the cyano for nutrients by increasing light 2500 lux a week for eight weeks. I landed at 40,000 lux with a metal halide in a a 20in deep tank with a Squamosa that grew an inch in 6 mo.

Interestingly two corals stayed brown and did not grow.