i dont beleive the above statement is true i have so much coralline that i scraped it off my back wall grinded it up into a powder , gave it to my freind who had just started his tank and had no coralline , he dumped that powder in , and 2 days later the spores loaded him up with coraline ........ because of this , i have coraline to sell , but with adequate calcium levels you should be groqwing the coralline pretty quick here