As an indication that your water quality and lighting is good, Coralline Algae will grow nicely. It will cover most anything, from Live Rock to snail shells, usually appearing first on plastic (pumps and plumbing). Seeing tiny dots appear on equipment in my tank, I was so excited to know I had the ratio right. If you scrape any off the glass walls of your aquarium, the chips will 'seed' your tank for more growth. Use a credit card on acrylic to avoid scratches. Reef safe.