Light Meter Question

Hey I just bought a light meter, this one:

http://www.amazon.com/gp/product/B003CHDFV4/ref=oh_details_o06_s00_i00?ie=UTF8&psc=1

Anyway the directions that came with it are sparse at best.

It's got a switch w/3 settings

#1 is for 0-200 footcandles
#2 200-2000 FC
#3 2000-5000 FC

When I have it on #1 or #2 it reads "1" on the display when placed under the grow lights, but if I move it in a shady area the number jumps up. Seems backwards.

When I set it on #3 I get a reading around 60 at the tops of my plants about 14" away. This is under a 600W MH

Anyway can someone explain this, what setting should I use and what the target should be? What does the 60 mean exactly on the #3 setting? 60 candlepower? How can I use this new toy to improve my grow?

Thanks

hmmm did you try to google the light meter and see if there is some instructions out there ? maybe it measure in Ft candles per sq ft. ?

mine shows in foot candles 1-10 (x1000) 1-3k is shady 3-5k is like a normal day 5-8k is a sunny day and 8-10k is like when the Sun is the most powerful (Sun provide about 10K Lumens at the most on a bright sunny summer day) I found that 3-5K works great for Veg where the plant don't need as much/strong light but in flowering only the Bud sites that receive +5K get really dense/hard/heavy





dunno if it helps in anyway ? btw its under a 600W HPS about a ft away

Yeah the website for the company has no additional information.

1 footcandle = 10.76391 lux
1 lux = 1 lumen per sq meter

Figong said:

1 footcandle = 10.76391 lux
1 lux = 1 lumen per sq meter

Click to expand...

OK thanks, but what is the ideal fc, lumen or lux?

I called the company and talked w/a guy and he explained when the meter was on the lowest 2 settings it was overwhelmed or over-capacity and I did not notice under the display there were conversions to be made. 1X, 10X, & 100X

So my reading of 60 on setting #3 means 6000 CP. What cp, lux or lumen should I be shooting for, I can do the math with the formulas Figong provided

Thanks again

AimAim said:

OK thanks, but what is the ideal fc, lumen or lux?

I called the company and talked w/a guy and he explained when the meter was on the lowest 2 settings it was overwhelmed or over-capacity and I did not notice under the display there were conversions to be made. 1X, 10X, & 100X

So my reading of 60 on setting #3 means 6000 CP. What cp, lux or lumen should I be shooting for, I can do the math with the formulas Figong provided

Thanks again

Click to expand...

Can also convert lux to watts.. if you wish to go that way - here's a website with calc for you: http://www.rapidtables.com/calc/light/lux-to-watt-calculator.htm

OK I get how to do the math, I just was asking what CP, lumen or lux was appropriate, or minimum, or ideal.

AimAim said:

OK I get how to do the math, I just was asking what CP, lumen or lux was appropriate, or minimum, or ideal.

Click to expand...

If it were me, I would aim for 5-7k lumens per sq ft.. mileage may vary on that one... but 5k is a solid answer for solid growth.. would not use the word optimal as there's quite a differing consensus as to what's 'optimal'