Live rock

Altec wrote:
What is that purple stuff on live rocks?

TIA

it is coraline a type of algae that is benificial or indicatave of the
condition of a marine tank plus it looks awesome once it has solidly
coated the back and side walls of your marine tank. totaly eliminating
the need for tacky backdrops. side note if you paint the outside back
wall of your tank black and roughen or sand the inside glass it will
accelerate coraline ahesion and growth. it also adheres to plastic
faster than glass.