oh i didnt say not to get it form you guys. you need some to be able to grow from. i and some others believe that it is the iodine that helps the coralin grown faster when it is more readily avaible. well in my tank before i had started to use the purple up i have a very small amount of coralin growth, barly growing on the glass. after a week or two of use i started to see the glass being covered more more at an almost expedental rate. I had done nothing to the system during this besides normal dosing. i had stoped doseing and after a week i could see the coralin growing as much or as fast. I also did a test when the back glass was fully covered. i scraped a patch away and let it grow back, it took more than 3 weeks to grow back. so the second time i took the same scrap off and used purple up from that day foward until it was totally covered. it only took about a week and half to two weeks...this was proof enough for me to use it on my new 7 gallon nano and the rock seems to be starting to cover nicely...this is my experiance. i had also found out about this stuff from jerry when he was using it in the zoo tank, im not sure what is thought were about it, maybe he will post as well.