If you go to Seachem's site you will find that they say just the opposite. Excel actually helps get rid of hair algae.

Hey Panaque, How in the world do you get your system to last 4 weeks?!?!?! I can barely get mine to last 1. I use a recipe off of plantedtank.com where I fill with sugar to the mark and dissolve 1/4 tsp of yeast in warm water and fill to the second mark. Mine goes gang busters for 4-5 days and then ...

I know that these kind of questions are a pain but I need a possible ID on a pleco I saw in my lfs today. It was labeled as a butterfly pleco but it doesn't look anything like the pics in the cat-e-log here on site. This fish supposedly stays pretty small, has the body shape of a typical pleco but ...

Have you seen it eat yet? Every now and then it seems that I get a cory that takes longer than the rest to acclimate. I'd give it a week before I got too concerned.