Here you go, straight from the reef world's chemistry expert.
http://web.archive.org/web/20021206232224/reefkeeping.com/issues/2002-04/rhf/feature/index.htm
Re: Light Friendly Clear Mesh Screen Cover for Open Top Tanks-Standard/Rimless-w/Pict
PM Dave and see if he has any clear mesh left. I bought some from him and made a top for my 120g, works perfectly and good pricing. Thanks Dave!