Hi;
You did hit the point. Live rock exists even at 200 foot depths where
light is dim.
Ilumination is one of the most over-rated fixtures of a sal****er
aquarium. A very expensive over-rated fixture.
Live rock doesn't need much light, even if the algae dies the rock stays
alive as long as the animals within are being fed.
Hard coral is another story. These types of anthozoans have an algae
incorporated within as a simbiont. If the algae is not doing its part of
the conditions get unbearable, the polyp will expell the zooxanthella and
will be able to live without it for periods of time. The drawback about not
having the algae in the symbiosis is the loss of colours, the main reason
for having corals in a reef aquarium.
I grew up in the Caribbean, I haven't seen coral reefs like those anywhere
else other than Australia and the IndoPacific, the probable birth place of
coral reefs. The majority of the time the water visibility is not great and
coral reefs manage to survive with little and poor light at depths of up to
100 feet.

jrs
"TheRock" wrote in message
news:kGZLf.2274$UN1.1116@trndny08...
Rock doesn't need light...algae does.
Is live rock really live ?

I believe it just accommodates, beneficial bacteria, worms, pods, misc
micro fauna and algae.
So I guess if your make your sump a refugium style sump then yes to the
light. 10,000K

right ?

"Harry Ohanian" wrote in message
. ..
If I put L.R. in my sump do I need lighting for it to stay alive?