Monitoring and dosing systems for dosing additives to water in aquatic environments, such as aquariums, swimming pools, hot tubs, and ponds, to maintain the quality of the water within tolerances and/or to control other aspect of the aquatic environment, such as controlling the growth rates of flora and/or fauna in the aquatic environment. Some monitoring systems disclosed include chemical indicator apparatuses submerged in the water and having multiple immobilized-dye-based chemical indicators for detecting the levels of multiple constituents of the water that contribute to water quality. Corresponding monitoring/measuring units include one or more optical readers for acquiring readings of the chemical indicators. Dosing can be performed automatedly and/or in an assisted manner via a dosing calculator and appropriate support systems. A variety of robustness features are also disclosed that can be used to assist the systems in ensuring that measurement readings are as accurate as possible to avoid improper dosing.