if you test 0 , why do you want one? the green algae on the glass that you have to scrape? that is corraline and other algae that is part of keeping a SW tank. if stuff didnt grow on the glass, you would have a big problem.
i just sent out my frag (ticket to recieve) this morning, boston should get it friday. slight delay as i was tracking down heat packs - i hope it makes it!