No one actually mentioned coraline algae growing "on glass" is good for coral growth. I just saw a lot of the tanks that I bought frags from have them on the glass. It seems that the owners do not want to scrape them off. I just assumed they want it that way.Deanos said:Wingo, who informed you that coralline algae growing on glass/acrylic is good for coral growth? On the rockwork, yes, but on the glass?!! Where aquarists allow coralline to grow is more of an aesthetics issue. I scrape it off of all glass except the back wall. Perhaps you should reword your poll question to "Where do you scrape coralline off?"