What lux meter should I get?

[onetrickpony]

What lux meter should I get?
Thanks
Ken

http://www.orchid-depot.com/shop/shop_lightmeter.htm $30.00

Or

http://www.aquaticeco.com/index.cfm/fuseaction/product.detail/iid/22118 $78.00

 

[crumbletop]

I'm no expert, but I have heard that PAR is what is worth measuring, not lux. You want to be able to measure the amount of useful light. I'm not sure how to do that and perhaps you use the same meter to do so. Just something I think I read somewhere...

Jack

 

[onetrickpony]

Hmm\
I am probably be wrong but
I thought par was the measurement higher the par number the more natural the light looked
Help please
Ken

 

[crumbletop]

PAR stands for (I think) Photosynthetically Active Radiation. I think it is a measure of the intensity of the wavelengths of light that most impact photosynthesis (400-700 nm?). I'm really way out of my element here though. Hopefully someone who really knows the deal will chime in.

Jack

 

[robsmith32]

par is measurement within the given range that corals use, lux is a measurement of human visible.. 2 different readings and wavelengths

 

[onetrickpony]

I want to build a lean to green house for frags
just trying to measure when I have too much or too little light
shade cloth or supplemental lighting
Ken

 

[bloodlamb]

Would a lux meter be useful to determine if the bulbs need to change?

For example if a new buld gives 2800 lumems I would change them when intensity drops to say 2000 lumens instead of just depending on a fixed schedule or my eyes.

 

[Rueg]

A lux meter would show the drop in intensity of the light.

 

[GreshamH]

This is what you want, a Quantum (PAR) meter

http://www.apogee-inst.com/bqm_spec.htm

Model QMSW-SS

(this one can do both electronic lights and sunlight + it has a sensor)