Anyone use a Lux meter to measure output?

[TheBeak]

It seems with all the different technologies in use, it sure would be nice if we could compare light output in a standard way (since we all know watts doesn't compare apples to apples)

Is anyone using a lux meter to measure actual output?

You can get fleabay lux meters for under 30 bucks shipped. at +/- 4-5% accuracy they would be all we need to get a nice baseline for lighting comparison going.

I think this will be even more important as we start to move into the LED age. since they run near 95% efficient, we are going to need lux to compare against PC, VHO, halide....

Obviously this method still has its flaws, since you cant measure at depth, but I'm thinking if we all measured at say 15 inches from whatever fixture we were testing, in free air (Again, I know water affects things, but I'm looking for a usable baseline.) and posted results.

something like:

Lamp Type: XXXX
Rated wattage: XXXX
Rated color temp: XXXX
Recorded output @ 15 inches: XXXX
Lux @ 15 inches- per gallon: XXXXX

I think this info, combined with the old Watts per gallon "rules", mixed with photos of growth results might reveal some really valuable lighting data. It would also be handy to monitor how our lamps were aging, if we re-tested our fixtures ever so often over time.

[TheBeak]

Me, on the 5G Nano hood I'm building now.

Lamp type: LED (1w luxons)
Rated wattage: 4
Rated color temp: 10K
Recorded output @ 15 inches: (I need a meter. If my 1w's output out a total of 250 ish lumens, and given that at 15 inches there is about a 1/2 meter spread. Insert bad math that should be 1000 lux?)
Lux @ 15 inches- per gallon: (given my shakey estimate with no meter, 200 lux/gallon.)

Looks plenty bright, but really "should" be way to little light given wattage. I'd love to know what comparable technologies outputted, since i can swap my 1w luxons (that should be in the 60 ish lumen each range) for some K2 stars, or add a few more 1w's (K2's can be run at 130 lumen each @1500 ma, but I dont know how long they will live at that level.)

...but DIY LED talk we can save for another thread.

form the wiki on lux:

Lux versus lumen
The difference between the lux and the lumen is that the lux takes into account the area over which the luminous flux is spread. 1000 lumens, concentrated into an area of one square metre, lights up that square metre with an illuminance of 1000 lux. The same 1000 lumens, spread out over ten square metres, produces a dimmer illuminance of only 100 lux.

[dobejazz]

I believe Wiskey uses a LUX meter to measure his light output

[know-it-all]

a guy in my reef club bought one

[Geoff]

i think there is a site out there that does most of what you are asking. i will see if i can find the link, it may be on my work computer though.

G~

[TheBeak]

was in a Target store today, and was looking at 6500k compact florescent screw ins.

the 10 watt advertises 580 lumens. (or just about the same as a 1W luxon, at about 60 lumens per watt.)

I wonder how other compact fluorescents stack up...

[Wiskey]

I do own a Lux meater with a submersable probe and use it to track light output over time, and test different types of reflectors and light types.

If you were to buy a meater though I highly reccomend an Appogee Par meter, this has the advantage of measuring Photosinthatically available radiation (the light our corals can actually use) over LUX which is visable light.

Whiskey

[TheBeak]

wiskey,

something like this?

http://www.apogeeinstruments.com/pdf...QSO_Manual.pdf

i have a nice fluke multimeter, so something like this that works with that might be fun. bummer is i dont really understand the outputted information.

it outputs the level of Photosynthetic Photon

Flux (PPF) and is measured in μmol m-2 s-1.

basically measures the ammount of photosynthetically available light. great for us that want to know, but i dont think to many on this board want to spend 170 bucks on a sensor, plus a couple hundred bucks on a decent meter.

i might get one just to tinker with, but i was hoping to get some measurements form other users rigs. compile some useable data.... know what i mean vern?

[mg]

Originally Posted by TheBeak

wiskey,

something like this?

http://www.apogeeinstruments.com/pdf...QSO_Manual.pdf

i have a nice fluke multimeter, so something like this that works with that might be fun. bummer is i dont really understand the outputted information.

it outputs the level of Photosynthetic Photon

Flux (PPF) and is measured in μmol m-2 s-1.

basically measures the ammount of photosynthetically available light. great for us that want to know, but i dont think to many on this board want to spend 170 bucks on a sensor, plus a couple hundred bucks on a decent meter.

i might get one just to tinker with, but i was hoping to get some measurements form other users rigs. compile some useable data.... know what i mean vern?

Our club bought that exact meter and as long as you are a paid member you can borrow it any time, well get on the list anyway. Works out that you can use it every couple months. It's nice when you are replacing bulbs and came in handy when I set up my frag tank to make sure the light levels were similar. It also gave me confidence that I can keep anything on the sandbed as the PAR there is still about 150 PPFD.