I use distilled water, never tested the Ph of it but its most likely 7.0 if the distiller is working properly. Sometimes your nutrients can help balance the soils Ph. I have some from purple cow called liquilife and biosupercharger. Both have a Ph of about 4 with humic acid listed in the ingredients. USUALLY your soil will balance itself out if its living soil. But if youre using salt based nutrients, youre gonna wanna test the runoff and adjust accordingly. Those salts are gonna slowly build up in the soil messing with the Ph and not allowing the microbes to live their best lives.
Youre doing right by your plant dude. Youre listening to her and finding good advice and solutions, the community here is fuckin awesome. Keep us updated!
Also, not sure if someone already mentioned it, but nutrients can be locked out (meaning the plant cannot access them) at certain Ph levels. Theres a chart online that will show you the best Ph for the absorption of specific nutrients. Your plant MIGHT be suffering from that. Based on waht i read here. Looked like your Ph levels were kinda all over the place, but i think i saw you say your runoff was over 8.0? WWWAAAAAYYYYY too high if thats the case haha
Best of luck dude!!!