seachem flourish excel has a reputation of getting rid of algae as one of it's "side effects"
you should however look into the reason behind your algae growth.
consider factors such as, photo period, color temperature of light bulb, how many plants are in the tank, is it cycled, etcetc.
algae is usually the result of light and nutrients (ammonia, nitrite, nitrates, phosphates etc...)
so you should look into what the cause may be
The algae is also saying. you really need water changes. there is apparently a build up of nutrients...