Marine question.. Light hazards to humans  10/6/08
Hi all, firstly let me say what a fantastic resource this site is! I don't think I’ve ever failed to find the right answer on WWM.... until now!
So the question, can viewing my aquarium at close quarters damage my eyes or skin?
<Mmm, "if" using some types of metal halides sans protective shields, you might, otherwise, only by long exposure... like a mild "sun burn">
The reason I ask is because the intensity and wavelengths of light (I run 234 Watts of T5 in 150 Litre tank) are not what can be called "natural", and in my experience in situations like this the health and safety bods would be recommending some sort of PPE to be worn! Furthermore, can T5's be more harmful than halides?
<Not as far as I'm aware, no>
I'm first to admit I spend unfeasible amounts of time observing my reef, so this question may be of interest all the other like-minded pet stone keepers out there!
I cannot find an answer anywhere in literature or on the web, possibly because nobody is asking! If you have any knowledge in this area it'd be greatly appreciated.
Thanks
Kevin W
<Relative to other sources of "trouble", this one is vanishingly small. Not to worry. Bob Fenner>

Re: 90 gal reef
Thanks for the follow up Steven, is there a metal halide fixture out there for me other than the space light that is light and could be hung above the tank?
<I am glad you wrote back. I just read an interesting article last night about double ended lamps vs. single ended lamps and I must admit now that I was wrong before. The entire article is based on dispelling myths about double ended lamps, primarily being that they are more powerful than their single ended counterparts. Basically, double ended lamps do not have a built in UV shield and are generally tested with a reflector while single ended lamps are tested without. This gives the data a skewed picture. The article is here http://www.advancedaquarist.com/issues/aug2002/review.htm>
I just haven't found any fixtures that can be supported above the tank. I
don't think it would be a good idea to place a metal halide unit right on top of the glass.
<Correct>
Any suggestions? Ideas? Thanks!
<This unit will be fine. Keep your LPS near the bottom, though. -Steven Pro>

Lighting up
Oh Bob I forgot to tell you. I bought a compact lighting unit for my 45 gallon tank. It contains two 55w bulbs (pretty bright) made the tank look incredible. I also bought a 30w Actinic bulb for my existing light strip that came with the tank. Everything looks good. They only thing I notice was an increase of the brown algae. This could be the result of a larger amount of water changed than usual. Would the increase of lighting produce the brown algae?
<Mmm, yes... at first... this "too shall pass"... as the system adjusts to more and different light/photonic energy>
But a word of advice to everyone don't look directly into the actinic bulbs while they are on your eyes will go crazy. Hey Bob if you post this message on your web site everybody will probably start looking directly at the light.
<You are a worthy strategist. I will add my comment as well. Looking directly into any artificial light source is ill-advised. Bob Fenner>
Thanks for your help.
David S. Garcia