Lux Meter

[pasenah]

does anyone know what to buy or how to use one?can a photography one be used?
any advice on finding out the lux would be great.
thanks
ben

[kim]

What would you use it for ?

A lux meter would be useful to indicate when a lamp is aged and due replacement (measure it when new, then monitor it). But it measures light according to the response of the human eye (red and blue is dark, yellow is bright), not according to the response of photosynthetic organisms (all colours are equally bright).

Given the enormous difference between the spectra of natural light and artificial light (from halide and fluorescent lamps), it becomes impossible to convert one form of measurement to the other.

If you want to work with corals etc. then a PAR meter is better. It, too, isn't a perfect tool, but it's an improvment. It's the form used by horticulturalists and marine biologists.

I think that the only "affordable" one is the Apogee (http://www.apogee-inst.com) Quantum Par Meter, which you can import or, if IIRC, buy from Midland Reefs. The probe is waterproof, which is great for in-tank measurements.

Sadly, it is still pretty expensive, so you need a serious amount of hunger !

kim

[pasenah]

hi kim, it would mainly be use by a friend at a lfs to see what the corals do at different positions. the lux can be recorded and used for reference.also to record how the lights are ageing.at least i think thats what he said. thanks for the info.
cheers
ben

[Reefworks]

I use the Apogee Quantum meter. As mentioned already this measures PAR and it's errors for various wavelengths is given. It's a good unit and cost me around £200. You would be amazed at the difference a couple of inches can make when positioning under halides!

[pasenah]

which is more important,lux, par or kelvin or do they need to work together.

[kim]

For what ?

If you mean maintaining corals, and you are using halides or fluorescent lighting, lux is close to useless, kelvin is totally useless and PAR is useful !

:lol:

kim

[pasenah]

its for maintaining corals with halides

[Reefworks]

It is the ammount of PAR that is relevent. Combine this with the spectral output of your lamps and you can see if you are providing your corals with the best wavelengths of light along with the amount of it.
HTH