Measuring light

[coolwaters]

im trying to get a quantum meter and a lux meter.

people said that a lux meter isnt a good meter for use when im measuring coral light requirements.

so im getting a quantum meter too.

 

anyone know how a quantum meter works?

[HecticDialectics]

They just use different sensors/calculations than lux meters. Lux measures 'brightness' (i.e. human eye) and PAR and PPFD measure photons (i.e. photosynthesis).

 

Useful articles:

http://en.wikipedia.org/wiki/Photosyntheti...ctive_radiation

http://en.wikipedia.org/wiki/Lux

http://www.reefkeeping.com/issues/2006-03/sj/index.php

http://www.reefkeeping.com/issues/2006-04/sj/index.php

[coolwaters]

coral dont have chlorophyll like plants do (their animals.) so i havent researched how they get energy from light yet...

 

what process does coral use to gain energy from the light?

[Deleted User 7]

Photosynthetic algea covering thier tissues. If my memory suits me correctly they are called..... Zooxanthellae. I may have spelled that wrong.

[coolwaters]

icic thanks for clarifying that Dr. Daggett.

 

so red and blue wavelength is the best color to grow coral.

[Ebn]

Get one of these with the separate sensor and be done with it.

 

http://apogeeinstruments.com/bqm_spec.htm

 

From what I read, corals really like peaks in the 450nm range, where two of the three types of zooanthellae are flooded (the 3rd zooanthellae is moderately affected as well). Also, according to Tyree, the greatest areas of diversity of life on the reefs have PAR values measuring 200 to 600 microE/m2s. You hit 300 microE/m2s and you will be able to keep just about anything.

[strangelove]

Get one of these with the separate sensor and be done with it.

 

http://apogeeinstruments.com/bqm_spec.htm

 

From what I read, corals really like peaks in the 450nm range, where two of the three types of zooanthellae are flooded (the 3rd zooanthellae is moderately affected as well). Also, according to Tyree, the greatest areas of diversity of life on the reefs have PAR values measuring 200 to 600 microE/m2s. You hit 300 microE/m2s and you will be able to keep just about anything.

 

What is microE/m2s? Just wondering.

 

I've got a whole bunch of photography light meters, it measures light, but it gives camera setting values. I was wondering if I could use it, and translate those light values to PAR values. Since PAR has to do with mostly visible light and my light meter reads visible light it should work right?

[HecticDialectics]

What is microE/m2s? Just wondering.

 

I've got a whole bunch of photography light meters, it measures light, but it gives camera setting values. I was wondering if I could use it, and translate those light values to PAR values. Since PAR has to do with mostly visible light and my light meter reads visible light it should work right?

 

From one of the articles I linked, "PAR is measured as PPFD, which are Einstein/m2/s or µmoles/m2/s. One Einstein = 1 mole of photons = 6.022×1023 photons, hence, 1 µEinstein = 6.022×1017 photons."

 

I'm throwing out a guess here, but I think camera/video equipment normally works off of lux... PAR is more of a biological science thing. Converting par to lux doesn't really work well because they measure different things with different units.

 

 

 

Also just a general point, zooxanthellae are actually shades of golden/brown in color. They aren't the bright vivid colors most people want in a coral. That's why light is important in coral coloration- too little and it turns brown (and perhaps dies if it's much too little). Too much (either too much of an increase over a short time or too much in general) and the zooxanthellae is expelled and the coral bleaches and dies. You'd want to reach a balance where the zooxanthellae can still live, but not flourish...