Algae Bloom (Green Black Yellow)

Algae Bloom (Green Black Yellow)

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Algae Bloom (Green/Black/Yellow)

The Problem: Water turns green, cloudy, and murky. Pool walls and floors become slippery and may develop green, yellow, or even black spots. Severe cases drastically reduce visibility and create a breeding ground for bacteria.

In-Depth Cause Analysis

Algae are microscopic aquatic plants whose spores enter the pool through wind, rain, dust, or swimmers. Their explosive growth is fueled by:
1, Sunlight: UV radiation provides energy for photosynthesis.
2, Warm Water Temperatures: Summer heat is an ideal breeding ground.
3, Imbalanced Water Chemistry: This is the most critical factor.
Unbalanced pH: A pH outside the ideal range (7.4-7.6) drastically reduces chlorine's efficacy (killing power).
Insufficient Chlorine: Free Chlorine (FC) levels consistently below 1.0 ppm cannot effectively kill algae spores.
4, High Total Dissolved Solids (TDS) Or Old Water: Water saturated with dissolved solids provides more nutrients for algae.
5, Poor Circulation & Filtration: Dead spots and areas with low water flow become sanctuaries for algae to multiply.

Recommended Chemicals & Detailed Application Methods

1, Shock Treatment (Oxidation)
Chemical: Calcium Hypochlorite (Cal-Hypo) or Non-Chlorine Shock (Potassium Monopersulfate - MPS).
Purpose: To deliver a massive dose of oxidizing power. This "breaks the back" of the algae bloom by destroying cell walls, overcoming their chlorine resistance, and oxidizing the organic waste they produce.

Application Method:
Perform at Dusk/Night: Prevents UV rays from burning off the chlorine before it works.
Pre-Adjust pH: Test and adjust pH to 7.2-7.6 to ensure maximum shock effectiveness.
Calculate Dose: Use a double or triple dose of shock according to the product label and your pool's volume. Severe green algae may require 3-4x the normal dose.
Procedure: Set the pump to "RECIRCULATE" to bypass the filter and prevent it from getting clogged with dead algae. Pre-dissolve the shock in a bucket of water and pour it slowly and evenly around the pool's perimeter.
Circulate: Run the pump continuously for 24-48 hours.

2, Algaecide (Prevention & Treatment)
Chemical: Quaternary Ammonium Compounds ("Quats") or Polymeric Algaecide. Quats are cost-effective but can cause foaming. Polymeric algaecides are more advanced, longer-lasting, and non-foaming, ideal for severe cases and prevention.
Purpose: Works as a supplement to shock. Its specific chemistry ruptures algae cell membranes. It is crucial for preventing recurrence and tackling chlorine-resistant algae types (e.g., black algae).

Application Method:
Add After Shocking: Apply algaecide several hours after the shock treatment, while the pump is still running.
Calculate Dose: Use the product's "Treatment Dose" (not the maintenance dose) as directed on the label.
Addition: Pour the required amount directly into the skimmer or slowly around the pool edges.
Follow-up: After 24 hours, a flocculant (see below) can be used and the dead algae should be vacuumed to waste.

3, Maintenance:
Once the algae is dead and the water is clear, backwash or clean the filter.
Restormal normal chlorine and pH levels.
Add a weekly maintenance dose of algaecide to prevent regrowth.