RubenD wrote:
I appreciated the comments, but can anyone give me a realistic way to
measure the amount of light necessary for a reef tank based on distance and
wattage or lumens?
There has to be a way, I pressume...


Ruben


Ruben,

There is not a way. For one reason the specific bulbs you run will
effect the light output you get without changing the wattage. A 6500K
iwasaki bulb at 250 watts in JBNY's testing give 605 par. While an
XM15K on the same ARO electronic ballast only produced 171 par. Less
than 1/3 usable light from the same watts.

Lumens will work better but lumens do not take into account if the light
is usable by the corals. You could have a bright red light, with lots of
lumens that would not keep any corals alive since the light would not be
usable by them.

Lighting is one of the most difficult items to decide on for a tank.
The best suggestion that I can give anybody is find tanks that are
similiar to yours with the same corals you want to keep and use there
lighting for a base. Or find people you know you can trust and ask them
for advice. Do not take the advice of any one person as gospel.

Kim

For some info on metal halide bulbs and PAR readings compairing the
amount of usable light check out this web site, it has most 250 watt
bulb/ballast combos listed.

http://www.cnidarianreef.com/lamps.cfm