I use a Gulfsrteam Mag-Float to clean my glass. You can buy 1 off this site (under dry goods). I usually wipe it around a little every day (takes about 5 minutes), and the algae never builds up. Like Ed said, some people don't like them but IMO it was the best cleaning investment I've made.
Oh! If'n you decide to try 1, they come in different sizes, depending on how thick your glass is. HTH