//////////////////////////// Why did it happen? Warmer Water: The newly painted dark blue lining absorbs more sunlight than the old surface, heating the water and creating a perfect breeding ground for algae.Nutrients & Heat: The pool is fed by the nutrient-rich Potomac River. High nitrogen and phosphorus levels, combined with June heat waves reaching 95°F, fueled explosive algae growth.Repainting Issues: Residual materials in dormant supply lines, paired with peeling paint along the bottom of the pool, exposed rough surfaces that are hard to keep clean.