Nutrafin Phosphate Reagent Refill #1 for use with Nutrafin Phosphate (0.0-1.0
mg/L) Test Kit. Phosphate levels should be monitored weekly. High levels of
phosphate, often the result of overfeeding or infrequent water changes, can
contribute to unsightly algae growth. Therefore, the
phosphate levels should generally never exceed 1 mg/L.