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.  Suitable for the H600 Pro Substrate, H600 Pro,  P700 Pro 2 and S300 Pro 2.  We recommend storing the pH electrode with KCl storage solution in the protective case.