Looks like I'm out of Lux

[karburn]

I purchased a lux meter (with a waterproof probe!) in an effort to measure the light levels at various depths in different tanks to assist with coral placement. What I hope to do is take a reading in a dealer's tank, for example, and use the meter reading to place the coral under similar conditions in one of my tanks.
I'm having trouble finding anything that tells the relative output in lux of the major types/brands of bulbs. (URI VHO, MH, etc.) I've read in Eric Borneman's book about lux levels, but I need to translate this to captive systems. I realize that if the meter read, say, "200" at a certain level, then one could position the meter in another aquarium until they got the same reading; but I want to do more than this. I need to learn how to use the lux readings to know when to change bulbs, etc. Without knowing what it SHOULD read in a given situation, how would I ever know if the meter is broken? The lux/lumen thing is pretty much meaningless to most reef people, but I want to use this meter to full advantage.

This unit was made (or at least distributed) by Ultralife Reef Products. It's a digital unit with a remote probe on a coiled cable, and the sensor incorporates a photo diode & color correction filter. There is a spectrum graph in the instructions that looks like an inverted V that peaks at about 560 nm. The instructions also include a correction factor for different types of lighting. The meter itself is calibrated under the Standard light tungsten source of 2856K. The correction table only has four entries, with daylight having a factor of X 0.95. "Fluorescent" has a X 0.97 adjustment. MH isn't included, and mercury vapor light has a factor of 1.05.

Based on other posts elsewhere in RC and other forums, it does not look like there is a source of information that will say "a 110W VHO tube puts out X lumens or lux at a certain distance". I'm just going to keep a log of readings, noting the type and intensity of lighting at whatever depth of water and the corresponding reading on the meter. I was just looking for benchmarks. BUT..if you have any tricks or know of any more information sources, Iââ"šÂ¬Ã¢"žÂ¢d love to have them.
:rollface:

 

[Anthony Calfo]

Actually, bud... the lighting industry (non-specifically) has decades/tons of spectral data on lamp performance and expectations. I have seen/read but not saved some of these works.

I really don't think it would be hard to dig it up (calling the lamp manufacturers you use for example... heehee, they will definately be inclined to giev you lux data for you to track and replace their bulbs regulalry!)

Also, use the bibliographies of the experts that have written articles and books on the subject. Check Sanjay Yoshi and his works. Also, chat with Dana Riddle of Riddle Laboratories (Hawaii) and Steve Tyree of Dynamic Ecomorphologies... who have both done extensive research on this topic.

Kindly, Anthony