Always test your pool water after heavy use or rain, as both can significantly alter water chemistry. Swimmers introduce oils, sweat, and contaminants, while rainwater dilutes chemicals and lowers pH levels. Testing ensures sanitizer levels remain effective and pH stays balanced to prevent discomfort or equipment damage. Use a reliable test kit to check chlorine, pH, and alkalinity, then adjust as needed. Prompt testing after these events helps maintain water clarity, safety, and comfort. This simple habit prevents algae growth, cloudy water, and costly corrections, making your pool more enjoyable and easier to manage.