Galactica Lux Meter for ios

[CastAway]

I wanted to share this with the club.

It's a free app for iPhone. It might be handy for tank-to-tank comparisons. Works with reflected and direct light.

I'm not sure of the details here, but think that lux is a better comparison than PAR when comparing basic light conditions from tank-to-tank. I'm not sure how differences in temperature and spectrum affect comparisons, if at all, when measuring LUX.

Maybe some experts can chime in....

 

[Mark75]

Have you used it Jeff? Sounds like a good way for me to drop my phone in my tank.

 

[Chriscrna]

Have you used it Jeff? Sounds like a good way for me to drop my phone in my tank.

You put stump remover in your tank. What's a mere phone?

 

[Mark75]

I am not worried about my tank,....my phone cost $129.00!

 

[AdamPhe]

When both are used together it's a great thing.

 

[Mark75]

Leigh Ann's tank=5,850 lux
My tank= <10,000 lux (meter only goes to 10K)

Now,....what does this tell us??

 

[CastAway]

Post edited.

 

[McMullen]

@saltyfilmfolks, time to chime in!

 

[CastAway]

Wondering about the seemingly huge spread between direct at the waters surface, and reflected off my coral from the waters surface. Could that be?

 

[CastAway]

Cameras/phones would have to be a variable in this equation I would think.

Lots of articles on LUX values on reefs, and recommendations for tanks, but they seem to vary.

 

[saltyfilmfolks]

Wondering about the seemingly huge spread between direct at the waters surface, and reflected off my coral from the waters surface. Could that be?

That's the amount of light hitting your eye. Light is cool that way. Not a reading that means anything to you and I. Only to a camera that is trying to correctly expose.
Also kinda why phones aren't goo light meters.

But in the case you just want the light hitting the coral. Or if you don't feel like putting the phone in the tank. Just the reading from the surface of the water.

 

[saltyfilmfolks]

Hey mark forgive the cut and paste. I'm am supposed to be working. Fortunately I'm the boss. So.
Google lux par conversion. Dana riddle. It's a bit old but the science still holds. It's just the problem of led are not wellresearched and no definite constant factor has been assigned. And depending on white blue the par changes. And red etc depending on what you can mix with the lamp.

Basically each source has a value the sun is 50. 100,000 lux devide by 50 is 2000 par

The idea being a guy took a t5 and a par meter and a lux meter side by side. And then did the math.


T5 are pretty well researched and Dana gives the constant value there. By reading and research a Chinese black box is a constant of about 63.
The better the spectrum the lower the constant.
Some t5 are surprisingly a constant of 38.
That's a lot of par and not much lux.

If you test your led light do it at 50. 55 and 60 and you'll get a pretty close average
Plus and importantly if you increase the lux by 5000 lux intensity you know it's about 50 to 100 par increase. Or decrease.

No the apps aren't all they good sadly. I tested a bunch. Galactic a for iPhone. And lux light meter by crunchybytebox for android. It takes a bit of fiddling and practice with a standard light bulb.
The $15 red lux meter from Amazon is one I own. Check my threads under lux meter upgrade it has pics of the meter.

Anything I missed?

 

[saltyfilmfolks]

Cameras/phones would have to be a variable in this equation I would think.

Lots of articles on LUX values on reefs, and recommendations for tanks, but they seem to vary.

CMeras work differently than Meters. A standard lux meter or foot candle for a camera is incedental. The amount of light hitting the disk. A camera is a reflective meter. Or for you camera nerds a spot meter. The amount of light reflecting from an object or light source. The camera cannot usually define between a bright object in the frame and a light bulb and will average it for you. You don't want an average of light skewed by a brighter object you want the amount falling in an area if incedence.

 

[saltyfilmfolks]

Cameras/phones would have to be a variable in this equation I would think.

Lots of articles on LUX values on reefs, and recommendations for tanks, but they seem to vary.

CMeras work differently than Meters. A standard lux meter or foot candle for a camera is incedental. The amount of light hitting the disk. A camera is a reflective meter. Or for you camera nerds a spot meter. The amount of light reflecting from an object or light source. The camera cannot usually define between a bright object in the frame and a light bulb and will average it for you. You don't want an average of light skewed by a brighter object you want the amount falling in an area if incedence.

 

[CastAway]

@saltyfilmfolks, can one compare PAR readings tank to tank, that are under different lighting fixtures and types?

For the example, if my friend and I both measure 200 PAR at the sand bed, with a 24" water column, but he runs Radions and I run some off brand, or he runs more blue and I run more white, what does it mean? Is there any reason to think corals should do similarly?

 

[saltyfilmfolks]

Par is actually influenced by nearby color as well as shading. I.e. An empty tank with a blue background will have higher par than a black one. An empty tank with a white background will have a higher par than a black one. Same with sand.

Then there is still the weird experience I and many have that some corals just seem to like more blue.

And then......... What color is your blue and what color is your white
The way a manufacturer colors those is also directly related to par.

And
Blue according to all research actually has less par.
Mainly IMO it lacks the rest of the spectrum. I.e. A super blue has less then a 20k or 14k as the blue only covers 430nm to 460nm or so.

A more fair test would be to do a black box test. Test the light in a black box. I'd love to do that.
Then I'd put it on a tank and see what happens. Just to see if the higher par has the better PUR

 

[CastAway]

This helps. So, the readings give one an idea of what's happening inside the tank, but no comparison can be drawn between readings from different tanks.

Thanks!

 

[saltyfilmfolks]

Also why a lux meter is cool.
Also you'll see at t his if you look at a lot of PAR charts in Google image searches.

IMO going point by point and coral to coral w a par meter is really not giving the big picture.