The Aqua Master Tools replaceable pH electrode is easy to connect using the BNC connector. Due to the long double junction pH electrode, it has a longer service life. Over time, pH electrodes age, with proper care and regular cleaning, the lifespan is extended. However, over time, the reference liquid in the electrode will become contaminated and the electrode will respond more slowly or stop working altogether. The electrode will then need to be replaced.We recommend storing the pH electrode with KCl storage solution in the protective case.