The present disclosure provides methods for evaluating daily ammonia exposure based on a single fasting ammonia blood level measurement, as well as methods that utilize this technique to adjust the dosage of a nitrogen scavenging drug, determine whether to administer a nitrogen scavenging drug, and treat nitrogen retention disorders.

Multi-parameter water analysis system with a water parameter sensing device configured to wirelessly provide detector data and a smart phone displayable indicator of water analysis test results that are calculated by an analysis application that is updateable via a cloud-based data resource to account for a manufacturing change in indicator chemistry and/or an improvement in test result display. The water parameter sensing device includes an optical sensing apparatus configured to detect light from each of a plurality of indicators for different parameters when the indicator and a chemical parameter are exposed to each other, a processor to process information of the detected light, and wireless communication circuitry for communicating detector data based on the information about the detected light to a remote device. Social networking of water quality data allows sharing to other users.

Systems, methods, and software that measure a plurality of error values each related to a different condition of an aquatic environment monitoring system including a degradation in a chemical indicator due to photo-aging, a degradation in a chemical indicator due to water-aging, a physical contamination of a chemical indicator, an illumination imbalance related to an optical reader, a degradation of a light source of an optical reader, a contamination in water between an optical reader and a chemical indicator, a displacement due to friction between a chemical indicator apparatus and a monitoring unit, an error intrinsic in a chemical indicator, and an error in distance between a chemical indicator and an optical reader. The plurality of error values are used to determine a confidence level that is compared to a threshold value associated with the monitoring system. A correction instruction is generated for correcting one or more of the conditions.

In one aspect of the invention, a method includes determining an amount of carbon dioxide (CO.sub.2) in dialysate flowing through a dialysis system using a CO.sub.2 sensor associated with the dialysis system, determining, using a pH sensor associated with the dialysis system, a pH level of the dialysate, and calculating a level of bicarbonate in the dialysate based at least in part on the determined amount of CO.sub.2 measured in the gas and the determined pH level of the dialysate.

Multi-parameter water analysis system with a holder removably engageable in an enclosable water chamber having an inlet and outlet in line with plumbing of an aquatic environment and allowing water from the aquatic environment to enter the enclosable water chamber for a chemical indicator of the holder to indicate a physical change via an optical reader, the holder configured to move with respect to the optical reader at least in part due to a motive force provided by the flow of water from the inlet in the enclosable water chamber.