Light Spectrum - How to check

[skozzy]

What instrument is needed to test the "Light Spectrum" of my lights ?

I have been putting up with a red slime and brown alge and some yellow/green
shaded alge problem for several weeks to a month and more recently green
hair type alge was starting to cover my rocks, I was thinking at first it
was due to phosphates, so I went crazy with water changes, still not good
doing that. But after talking to a person that has been in the marine game
for several years, he rattled off several things that could be at fault, we
ruled out all but the lights. And it's looking more and more like that is
the real cause of my problems. But to be sure I would like to test the
lights and find out.

The unfortunate thing when buying all this marine gear, your are realy at
the mercy of the salesman, I was told when I bought my lights that the
fluros are daylight tubes and the metal halide is a 10k 150watt. After
describing the type of light I get to this new person he thinks that my MH
is around 5-6K and my tubes are nothing more then just triphospher or
similar bright tubes.

Tonight one of the fluros is going to be replaced with a Power-Glo tube made
by Hagen, from that I should be able to compair the fluro with my current
one. As for the MH, well it's expensive and I will change it to a different
bulb when funds are available.

-Andrew

[Matthew Comstock]

skozzy wrote:
> What instrument is needed to test the "Light Spectrum" of my lights ?
>

The spectrum is not so easy to check. You need a spectrometer. Even a
cheap one is around $1500. You could check your local university, they
might have one that you can use. (you'd need to bring the light to the
university however)

All you can do is compare visual colors, but that can be wildly
inaccurate. 12kK looks a little bluish, but I usually can't tell much
difference below 10kK.

-mat