Lux meter( get the most from your lights)

Migro shane has done a comparison, and the lux meter on playstore developed by dogger is the set up I use , its not 100% but better than guesstimations on my old lux meter , I like shane he don't talk poop , and I want his array possibly  😆 

@jacks_farm Thanks man. Free toy's

@jacks_farm Good info man. Like you said just use it as reference or benchmark. I have dimmable, wide spec LED and no idea what the "proper" setting. But like you said, tune up the old lights, get the level checked. I have two lights in line and had them spaced symmetrical, and thought the over lap was correct. I would have bet good money that the middle was covered better than it was.  And then I only had to move them together a very small amount. Now the numbers are much more consistent. A little tweak here and there and for free.  Now I'll sleep better.  Thanks JF

I am glad that @woolieback mentioned Shane from MiGrow. He also has a video where he buys a cheap lux meter from amazon and then uses a tent to plot the values and then compared them to his apogee par meter. He gives the average ratio between them and a graph showing that it is accurate up until just over 40,000 lux and after that the correlation/ratio between lux and par no longer held steady. Being the nice man that he is, he offered up the exact model # for the lux meter. I bought the identical model and in theory, it should have the same sensor in it as the one Shane tested.

I have used it regularly so that I can keep my light close to the canopy to save money on power because I can tell how much I can turn it down and still be giving my plants 800 or slightly more par worth of light.

I use CPU Z for Android that reads all sensors including the lux sensor that is in nearly all phones now

So I down loaded the the Lux meter, Looked up light recommendations and I found 

clones and seedlings - 5,000 - 7,000 lux

veg - 15,000 - 50,000 lux

flower - 45,000 -65,000 lux

max - 75,000

So I moved my light to about 18" - 45cm away from 12 day old seedlings. I adjusted the dimmer to about 12,500 lux across the plants, and now my lights are barely on. When I did my measurements, I had my phone elevated to the top of the seedlings, and the lens of the phone was located directly above the plant each time. As consistent as I could get it. 

So correct me if I'm wrong, but my idea is to maintain the 18"-24"/45-60cm and use my dimmer along with the meter to increase light throughout grow. Yay-Nay? I love my lights, they just don't come with detailed info. I mean they have really cool specs and pretty graphs, but I'm still holding the dimmer in my hand with no calibrated dial face. Then after using the meter I found that the smallest change to the dimmer was a huge increase in Lux at different distances. So manufactures recommendation was WAY to much light, or could easily be if not careful. So the meter appears to be another good tool, will have to learn more.  Thanks again for the thread, much appreciated.

@woolieback  Yep. thats it.

@woodi2 thats the 3500k , the 4000k is different , thankfully for as long as I have been growing with leds migro shane has made sure out of the big 9 PFD isn't one of them that is lacking