Aquarium pH is a parameter that is constantly changing. Because of this, it’s almost pointless to test it with the traditional titration-based test kits. Instead, it’s best to measure pH with a properly calibrated probe and monitor. This allows the hobbyist to continually take readings in real time, giving much more accurate results. Titration test kits for pH aren’t very accurate if the sample has been sitting out for even a short time, and the surrounding environment can drastically change the readings depending on CO2 concentrations in the air.