What colour is algae? Sherralyn October 01, 2018 23:24 Updated Follow Algae can come in several forms. Pink, green, yellow or brown film or slime. We suggest using Poppits Pool Algicide to get rid of it. Related articles When adding algicide, do I need to clean my filters? Why do I have a brown scum line after using poppits pipe degreaser ? Can I use Bromine tablets & floating dispensers in my spa? Why do I have green spa water? Why has my sanitiser use increased and water is still cloudy? Comments 0 comments Article is closed for comments.