My tank has been up for over 2 years now and I just cannot get much coralline to grow. Seems like it does ok on the rock but none on the back glass and barely any on the overflow for a tank being this old. Whats the secret to success? Here are my parameters, CA 500 NO3 15 phos 0 KH 10 Salinity 1.025 I do a 15% W/C every week.