Calculateur de Risque d'Algues | Calculateur de Bassin
Évaluez le risque d'algues avec un score de 0–100 et des recommandations de prévention.
How to Use the Algae Growth Risk Calculator
Enter daily sunlight hours (how many hours of direct sun the pond receives), water temperature, and the current nutrient level (based on fish load and fertilizer run-off). The calculator returns a 0–100 composite risk score.
Risk levels: Low (0–24) — minimal action needed. Moderate (25–49) — consider UV clarifier and barley straw. High (50–69) — add surface shade with lilies and reduce feeding. Very High (70+) — immediate intervention: water change, UV upgrade, and nutrient reduction.
The score is a leading indicator, not a guarantee. Algae blooms also depend on pond depth, circulation, and fish stocking density. A UV clarifier is the most effective single measure for green water algae — size it at 10–15W per 1,000 gallons for full sun ponds.
FAQ
What causes algae blooms in a pond?
Algae thrive when sunlight, warm water, and nutrients (nitrogen, phosphorus from fish waste or run-off) align. A pond receiving 8+ hours of direct sun in warm weather (75–90°F) with high nutrient load is at very high risk of a bloom.
How can I reduce algae risk?
Shade the pond with water lilies (covering 50–60% of surface), reduce fish feeding, add barley straw or beneficial bacteria, use a UV clarifier, and perform regular 10–20% water changes to dilute nutrients.
At what temperature do algae grow fastest?
Most pond algae (including green water algae and blanket weed) grow fastest between 70–90°F (21–32°C). Growth slows significantly below 60°F (15°C) and nearly stops below 50°F (10°C).