Finally able to get a "somewhat" stable pH after w/c. Bought a Malawi/Victoria buffer product that says it will keep pH between 7.8 - 8.2., when adding 1 tsp./10-20g. A few days ago did a 15% pwc and added 2.5 tsp. of buffer. pH b4 w/c ~ 8.10, 6hrs. after it bottomed out at 7.87. Within 30...