Why no purple algae?

[Ron99]

From the information I've seen I questions how much biological filtration comes from our rocks, especially now with so many people using dry rock. it is missing so much of the microfauna which are thought to be responsible for actually facilitating water movement in and out of the rocks. Secondly, the corraline will only cover the surfaces that are lit so a good portion of the rock won't have corraline algae on it and thus still be accessible for filtration. And I suspect water and nutrients can move through the corraline algae to the rock surface below.

In any case, I have access to some interesting experimental chemical coatings that just might prevent algae growth on glass and plastic. I'm starting some experiments. Stay tuned...