I think excel will help you get rid of the algae, but you have to administer adequate lethal level to the algae. According to excel instruction, you have to dose 5x after WC and 1x daily thereafter. When I had algae problem, I dosed 5x after weekly 75% WC and 2x daily thereafter, and the algae were gone in few weeks. The 1x daily is for liquid carbon, not enough to suppress algae IMO. I dosed 5x to the tank prior to filling up, so the effective dosage could be as high as 20x temporarily during lower water levels. The idea is to blast the algae, while fish can tolerate higher short term dosage. Glutaldehyde is an ingredient of SeaChem Paraguard which is formulated at even higher dosage than 5x. I’ve done it many times and my fish have never shown any ill effect, but make sure the filling water distribute the excel evenly. Be careful with shrimp though as I have no experience on how shrimp will react.
Excel is only a temporary fix, and if your underlying causes of algae is not fixed, it will return.
Excel is only a temporary fix, and if your underlying causes of algae is not fixed, it will return.