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...

Thanks for all the info here.. I see the topic to a U turn here haah.. Anyways turns out it ist bad I have none..

hmm, I was just looking at 4 tanks in the garage :mrgreen:

I like the different color of the hard algae, and for those worried about filtration, pull a covered rock out and look on the bottom... and the rock these guys are getting today are way more porous than the rocks we used 10 years ago, I am amazed with the light rock that can be had easy nowdays.

Steve