does pH change after watering?

say i'm using very hard water for my watering. If I pH it to 5.8 now, and leave the water standing, in a few hours it will be up to 6.5 at least, and a while later back at 7.8. This is granted, and I don't think there's much that can be done about this, if anybody knows anything i'd like to hear.

but say i use the water for my coco. Will the pH of the water shift up when the water is in the coco? or will it stay as it is?

I believe coco doesnt change pH. (not 100%)

what are you using to ph balance your water?

and have you tried to let it sit out first and then balance it?
because the stuff evaporating might be changing the pH

it's true that it's best to let sit and aearate before balancing
I use GHE liquid pH down

but I wasn't asking if coco changes pH - but rather if the solution in the coco changes. anyone knows?