I added 5 Mollies (2 black & gold marble, 2 silver) to my 10g tank about 3 weeks ago. Ammonia and nitrites were both 0 before I added them and have remained so....
A few days after I added the fish: ph: 7.4/7.8, kh: 6, gh: 9
1-2 weeks later - ph: 8.2, kh: 8, gh: 13
Fews days old tap water -...