Scenario... 55g, 14 mbuna two canister filters, tank has been established and stable for years, ammonia is always zero, temp always 78f, never overfeeding. Did half tank water change day prior and I have a habit of checking pH after a big WC
since I had a pH crash once before right after the WC
. So, a day after the water change, fish are fine eating well, couple of hours later they are all gasping for air on top and the surface is LOADED with bubbles! I knew exactly what to check for and sure enough, pH is way under 7. Quickly mixed some baking soda in water and kept slowly adding it till the pH reads around 8.2. By now some of the fish are laying in their side and some just floating lifeless on top. Within an hour they all seem to have gotten over it, following day they are all fine. Please someone educate me as to why the drop in pH a day after a WC
? By the way, my tap water pH is always around 8.2.