What colour is algae? Sherralyn June 14, 2018 06:03 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 How do I switch to BioGuard Armour if I have been using Lithium? Do Poppits test strips have an expiry date? Do I need to use poppits test strips with poppits chemicals? Comments 0 comments Article is closed for comments.