| | Re: First NPT, Issues
Safe T Sorb is dropping your pH and the plants don't like it / are adjusting to the new parameters. When using any of the montmorillonite clay substrates this will occur for the first few weeks or even months depending on which one you use and how soft you water is initially. If your tap water is hard the effect shouldn't last for long.
Frequent, as in daily or every other day, water changes are you best bet. Also, raising the KH as you did should help too. Whatever you do Crypts like consistency.