Also how much excel should I use? I don't want to harm the fish or the vals...The reason why I don't want to remove the vals is that they are the dominant feature of my tank. Without the vals the tank would be very empty.
Here's a picture:
As you can see the algae is covering the sword leaves on the left as well as the driftwood, rocks, gravel and back glass. It's less obvious in the picture but there is algae also getting caught in the filter. It's gotten worse since this pic was taken and there is algae branching across the surface and growing on the caulking in the corner where I can't scrape it off.