I’ve been having a high ph of about 8.2 in my ten gallon freshwater tank and 3 gallon Betta tank. Two days ago, I did a ph test that said my Betta tank was now at 7.4-7.6. Today, it says my 10 gallon tank is 7.4-7.6. Today, I also did a ph test in the Betta tank after a 50% water change and it’s now saying 8.2. I tested my tap water and it’s 7.2. How did the ph change so much in 48 hours? My Tanks do not have any plants right now. My 10 gallon has a molly, 4 shrimp, mystery snail, and African dwarf frog.