Guppy update may 31st...
Guppy is doing well adjusting back to my tap water treated with Prime.
After talking with oldfishlady, who has been raising betta's for over 20 years, the PH is probably not what made him sick, it was probably the ammonia which the Prime takes care of. She said that the PH should not be a big issue, considering he has lived in it happily already for so long.
She gave me instructions on how to use Indian Almond Leaves (IAL) to help lower the PH naturally and slowly, which I will try ones they get here.
I will try this method, the key is to be very slow about anything that is done.
Guppy's vission is back and he is adjusting to seeing again. Currently he is chasing food even to the bottom of the tank if some happens to sink, and flaring at anything and everything. Very active today and he seems happy. He still take long rests between swims but overall is looking good.
No more white spots detected and no more pieces of his fins are missing. His tail is starting to heal and I am keeping the water super clean for him to make sure he continues to heal.
His water remains clear thought the process. it will take me a few days to fully adjust him back to the tap water PH but slow is the key so I am not worried - and I am still keeping a very close eye on him. he is adjusting well though.
Thank you to everyone who helped out, even those who yelled at me. LOL
I am sorry if I got mad or frustrated, I just want my elderly fish to live as happy a life and for as many more years as he can.