i use tech a and tech b, and kalkwasser regulary and the coral line has blossumed quickly, i'd say deep purple colors covering entire rocks in 3-4 months.
There is a web page that i saw that sells coraline algae "pegs" or sticks, I guess you put them in your rock and it promotes growth. I dont know the exact address but is out of hawaii i beleive,
something like indopacific reef farms, or indopacific someting or other. anyways, the guy that runs the company used to be a big time clam collector, or sometingl ike that.