Hi, how you doing.
In myhome place(Guadalajara, México) the pH of the water is around 8.2 and the hardness is medium. I always use bottled water that has a pH of 7.0 but invariably tends to become alkaline. I have a 6 year old female axolotl and I have never seen any problem with these parameters as long as you maintain an adequate temperature and constant water changes to avoid ammonia (wich rises or become dangerous with alkalinity as I understand), so I recommend you not spend your money or effort to combat the pH and better observe any signs of disease..... and of cours, enjoy your axie.