In the absence of free ammonia the unit will assume a yellow or faint yellowgreen color. It is normal for the dry sensor to have a greenish hue. It may take up to a few days for a dry sensor to equilibrate with the water. No sampling of water chemicals or test procedures are required. The presence of the free ammonia is detectable continuously with a response time of about 15 minutes. Response to decreasing ammonia is slower requiring about 4 hours to go from TOXIC to SAFE on removal of ammonia.
INTERPRETATION As little as 0.02 mgL of free ammonia will produce a greenish hue on the detector surface. This corresponds to a total ammonia both ionized and free ammonia of 0.25 mgL in marine water at pH 8.3. In freshwater at pH 7.0 this corresponds to 3.6 mgL total ammonia. Free ammonia is much more toxic than ionized ammonia. As free ammonia the ALERT color corresponds to about 0.05 mgL ALARM to about 0.2 mgL and TOXIC to about 0.5 mgL. The ALERT concentration is tolerated for several days ALARM for a few days and TOXIC is rapidly harmful. This product is not recommended for use at acid pH
CARE No care is required beyond removing algae with a clean soft material. Avoid touching the sensor with fingers since skin oils can damage it. Do not use bleach soap detergents or hard objects to clean the sensor. Some dye medications may discolor the sensor. Sensitivity improves with age provided the unit is not allowed to dry out however drying does not permanently impair the unit. For maximum sensitivity the unit should be read under natural daylight or daylight