Cheap light meter

[Ermin]

Where can I find a cheap light meter to measure the light output of my MH? I want to check the bulb output when new and recheck once in a while to figure out when to change the bulbs.

Thanks.

[PerryinCA]

http://www.arabidopsis.com/main/cat/PPF/ppf.htm

There's a link to where you can find information and pricing on some "quantum meters". These are actually PAR meters. The sensors can be used in combination with a multi-meter.

I think all the products on that page are Apogee. The Apogee is good for the price. It underestimates at the 400-500nm, but over-estimates around 650-700. But, for only 100 it can't be beat. The LiCor meter is better, but costs about $400 more.

Lux, and Lumens aren't going to help you ascertain the info you want.

Hope this helps.

-Perry

------------------
Some call it evolution,
And others call it God.
Each In His Own Tongue (1908)
William Herbert Carruth 1859-1924

[Ermin]

Perry,

Can you elaborate on why you said, "Lux, and Lumens aren't going to help you ascertain the info you want."?

Thanks.

[PerryinCA]

Well, Lux and Lumens basically measure visible light. I probably siad that the wrong way, and I guessed you were looking to find the amount of light you are giving your coral. If thats not the case I have misled you.

Anyway, the Lux and Lumens are measures of light from purple to red end of the spectrum. They will measure all the wavelengths. PAR, characterized often as PPFD (Photosynthetic photon flux density) is the light that chlorophyll and asessory photosynthetic pigments will react to. A PAR meter/sensor will pickup those wavelengths, and give a readout in einstiens per cm squared per second. That value is what most researchers and hobbiests use to compare lighting for thier reefs.

Hope that makes some sense...[img]/ubb/smile.gif[/img]

-Perry

------------------
Some call it evolution,
And others call it God.
Each In His Own Tongue (1908)
William Herbert Carruth 1859-1924

[Ironreef]

if your using to measure intesity =loss of par it should work. ppl have used them to measure lights over braces and when they get old. They can tell a diff.