This is a perfect plan bro...
Could I possibly resolve my issue without having to add RO and that stuff too?
OC+ Just add water!
If my PH was 8-9...whew...
-Go
If you're growing in soil.....and your TA is within spec....there is absolutely no reason you couldn't water with pH 8 water. The soil has more than enough buffering capability to handle that....no problem.
On the other hand, if your TA is high, watering with pH 6.5 water is going to create nothing but trouble....because the bicarbonates build up in the medium.
The only time I'd pH water is if I was growing in a sterile medium, like perlite. The reason is because perlite has zero buffering ability and the nutes won't be available at a high (or low) pH.
But in soil, there is no need to adjust pH....the soil does that for you. Just think of a pot of soil as a great big batch of pH down. Except, instead of adding soil to water to lower the pH, you're adding water to soil.
Again, if the soil is rich in organic matter; guano, worm castings, blood, bone meal, kelp, etc. the pH is going to be very low. So, you add some dolomite lime to stabilize it. If your water is really alkaline....add less lime and water the pots a few times before you plant, in order to let the alkaline water raise the pH a bit.
Or, better yet, mix tap with RO to get the TA in check.
Now, the following is my opinion. What I said up there ^ is fact, but my OPINION is:
Soil growers overfeed, over water, have poor environments and all sorts of other problems and instead of taking it personally, that they F'd up their plants.....they blame it on pH.
There are millions of normal folks who grow vegetables in their backyards who never even considered pHing their water. Most public water companies provide water that is able to grow plants in soil. It's up to us to provide the soil.