New here and need to find a good test kit,pool is 20k gal,ig vinyl,1.5hp pump,250lb sand filter.My problem is hi phosphates.Pool store has made $1000.00 this yr alone and now my pool is cloudy w a greenish tint.All i have is test strips but the last time i took a sample in phosphates were over 1100ppm.Our water is terrible here,brown water at times and im considering switching to salt?