Table of Contents
## Understanding pH
pH measures water acidity on a 0-14 scale. Most freshwater fish thrive between 6.5 and 7.5. African cichlids prefer 7.8-8.5. Consistency is more important than hitting an exact number — avoid chasing pH with chemicals.
## The Nitrogen Compounds
Ammonia (NH3/NH4+) is produced by fish waste and is toxic at any level above 0 ppm. Nitrite (NO2-) is the intermediate product — also toxic. Nitrate (NO3-) is the end product and is tolerated up to 20-40 ppm. Test weekly with a liquid test kit.
## Water Changes
Regular water changes are the single most important maintenance task. Replace 25-30% of tank water weekly with dechlorinated water at matching temperature. This removes nitrates, replenishes minerals, and keeps fish healthy. Gravel vacuum during changes to remove detritus.
pH measures water acidity on a 0-14 scale. Most freshwater fish thrive between 6.5 and 7.5. African cichlids prefer 7.8-8.5. Consistency is more important than hitting an exact number — avoid chasing pH with chemicals.
## The Nitrogen Compounds
Ammonia (NH3/NH4+) is produced by fish waste and is toxic at any level above 0 ppm. Nitrite (NO2-) is the intermediate product — also toxic. Nitrate (NO3-) is the end product and is tolerated up to 20-40 ppm. Test weekly with a liquid test kit.
## Water Changes
Regular water changes are the single most important maintenance task. Replace 25-30% of tank water weekly with dechlorinated water at matching temperature. This removes nitrates, replenishes minerals, and keeps fish healthy. Gravel vacuum during changes to remove detritus.