I just came home from MACNA last weekend (GO NEXT YEAR, everyone!!!!!), totally psyched to get back to my neglected tank and clean it all up. First project: scrape algae and coralline algae off the glass. I started with one of those razor blade scrapers on a long handle from the LFS
(or actually Drs. Foster and Smith, I believe). There was so much thick coralline that within a minute or so, the razor blade was totally bent and destroyed. I went to a hand-held single-edged razor blade (only about one inch long, as opposed to maybe two inches of blade in the holder), and it worked like a charm! There are only a couple of small patches in the back which are too thick for this smaller blade and my hand to tackle.
Anyone have any thoughts on the problem of the really thick deposits??
Anyway, I've always relied on the old basic single edged razor blade and I guess I'll stick with it. Really cheap by the 100-pack at the local hardware store.
Glass vs. acrylic: Razor blades won't damage glass, but don't use them on acrylic.