For fish keepers, mastering the essentials of aquarium care is crucial to maintaining a healthy and balanced aquatic environment. After all, happy fish make happy fishkeepers, right? There is a wide range of parameters to monitor. However, the most critical factors to understand are KH (carbonate hardness), GH (general hardness), and PH (potential hydrogen) levels. These parameters play a significant role in the well-being of your aquarium inhabitants and can impact their health and longevity. This article explains aquarium KH, GH, and PH's roles in creating a balanced aquatic environment and practical advice on testing and maintaining these levels for optimal fish health.