Getting Rid of Swimming Pool Algae

Ask a question here Andrea and Paulette go long on algae—the real science, the field diagnostics, and the no-nonsense remediation that actually works on a Tuesday in August when the phone won’t stop ringing. Pulling from training content and field notes, they break down how to tell algae from look-alikes (metals, pollen, fine dust), why water balance and sanitizer demand dictate outcomes, and how to choose the right kill-sequence for mustard/yellow, black (cyanobacteria biofilm), green blooms, and stubborn pink slime/white water mold co-contaminations. They also reference Rudy Stankowitz’s book, How to Get Rid of Swimming Pool Algae (Amazon), for deeper reading on species behavior, biofilms, and step-by-step playbooks that complement today’s talk. Chapter Markers / Timestamps 0:00 – Cold open: “Is it algae… or just copper?” 2:12 – Why algae wins when demand beats delivery (sanitizer kinetics 101) 6:45 – Field ID: green, mustard/yellow, black (cyanobacteria), and the “not algae” suspects 12:10 – Water balance triad: pH, TA, and CYA’s impact on free chlorine efficacy 17:38 – Brushing matters: mechanical disruption vs. biofilm defenses 22:30 – The mustard/yellow protocol (when and how to go higher on FC) 27:55 – Black “algae” = cyanobacteria: surface penetration, heads vs. roots, patience game 33:20 – Filters as crime scenes: clearing, backwashing, and when to deep clean 38:05 – Phosphates: food vs. famine—when removal helps and when it’s a red herring 43:00 – Borates as drift control and slime deterrent (what they can and can’t do) 47:18 – AOP/UV/ozone: supplemental oxidation for heavy bather loads 52:40 – Look-alikes roundup: metals, pollen, plaster dust, and “dead algae” myths 57:15 – Off-season & startup traps: winterized pools, spring turn-ups, and biofilm seeding 1:02:10 – Rapid-response checklist you can hand to a tech Key Takeaways Identify before you treat. Color + texture + location + “does it brush off?” beats guessing. Sanitizer effectiveness is conditional. As CYA rises, the % of active hypochlorous acid drops; dose and contact time must adjust. Mechanical + chemical wins. Aggressive brushing and good circulation expose biofilms so oxidizers can work. Mustard/yellow needs elevated FC (and whole-pool exposure for toys, nets, lights, covers). Black “algae” is cyanobacteria anchored in porous surfaces; expect repeated disruption and sustained levels—not a one-and-done. Filters tell the truth. Restore flow, deep-clean media, and fix bypass/broken laterals or you’ll chase the same bloom. Phosphate control is situational. It can lower regrowth pressure but doesn’t replace sanitizer. Borates steady pH and deter slime, but they’re not an algaecide. Document everything. Photos, readings, doses, and filter maintenance notes protect you and speed future calls. Support the show Thank you so much for listening! You can find us on social media: Facebook Instagram Tik Tok Email us: [email protected]