well, I never bothered with messing up the PH. I do suggest, if you ever get a betta get one from a reliable person... people on here have healthy bettas, and depending on your area you can buy or get one shipped. I personally adopt out rescue bettas who are from the pet store or people who do not want them and would rather flush them. And all my rescues have always been extremely healthy when given to new homes.
I also would avoid walmart and such places. They do not have experienced people. if the store here ever had a fish section again, I personally would see to it that people like me, and my manager would be in that area because we know what we are doing. I've also found, Platies and Mollies are super prone to diseases, which can attack bettas.
If you ever give bettas (one of the users on here might be able to get you a healthy one if you are willing to pay a bit more than a walmart price) another try, PH can be lowered with driftwood, and raised with certain rocks. natural way is safer :)
and I am very sorry your fish died.
Breed for the breed, not for the money; the words any REAL breeder would understand.
You must know nothing in order to know all, for all is nothing and nothing is for all.