I have a VT Betta (Garp) for about 3 months in a 2.5 gal tank.
About 2 weeks ago, I had a sudden drop is ph level around 6.
I believe his tail was burned away about an inch, or intense fin rot, and I treated him.
His tail is growing back, but every time i check his ph level it is always decreasing for some reasons.
I do a 100% water change once a week, follow instructions on adding conditioners and Ammonia remover to make the ph level at 7.4~, soak decorations in hot water for 30 minutes, rinse the gravel 3 times in hot water, and replace filter cartridge. I always keep his temperature around 76~81 degrees.
After 2 days, Ph drops to 6.3~ and I add ph increase to make it around 7.4.
I never had this problem before until now.
Would there be something in the fish tank that is causing my ph level to keep decreasing?