Light for coraline algae?

[WiscSea]

How much light is necessary to sustain and/or grow coraline?

I bought a nice piece of LR with a good amount of purple coraline on it. I have it near the top of my 75 gal tank under the stock 48" single tube fixture. So far it seems to be doing fine, but not spreading.

I'd love to see it spread, or at least stay alive. Do I have a chance without a light upgrade?

Thanks!

[PiNaPLeX]

coraline is a "low light" algae, and should do fine with what you have, but better lights couldn't hurt :). other parameters to help it spread are calcium and alkalinity. keeing and eye on those 2 parameters has helped my coraline spread like crazy.