CO2 doesn't kill algae. If you want to combat algae (speaking generally, not just to you Flint) then you have to have the perfect balance. Excel (or CO2) is only one part of the puzzle, you also need to have adequate aeration (not to be confused with filtration) and the right plant selection.
There are reasons why plenty of low-tech tanks without CO2 injection don't have algal issues, they also have a balance; it's different balance to high tech tanks but it's all about the balancing.
So no, Excel does not get rid of algae unless you have the perfect balance. It helped in my tank but I also have high lighting situation, I dose Excel every day before my lights come on (best time to dose, you don't want CO2 high all day, it needs to have a natural fluctuation), I have medium-high light plants, and I dose Flourish Comprehensive twice a week with root tabs. I also have enough aeration to disperse the CO2 through the tank without killing my fish from too much CO2 and not enough oxygen.