WATER Questions, Am I doing it totally wrong???

Ok so I have had success by always lugging in gallons of store bought water. Distilled, Spring, Purified, whatevers cheapest. No PH or PPM testing, no oxgenation, just straight from the jugs. I have done it from start to finish, and never had issues. As this is pretty cumbersome I am considerimg the tap. So I assume a good PH /PPM pen would be a good investment? I have no idea the quality of my municipal water thus my prior method. So I am assuming that I just let it sit in a bucket 24hours and check that the PH is 6-7 for soil? Also I hear the PPM should be under 350-400 to be of decent quality to use? Does an air stone and bubbling make a difference? Finally, when mixing nutrients in said tap water, are the nutrients mixed first, and then the water PH’d?

Your municipal water district will have all the info you need concerning what's in your water (usually on-line). An airstone will speed up the dissapation of chlorine, which only takes a day anyway (I don't bother with chlorine/chloramines, the effects are so short lived). Add your calmag, mix, wait 15 mintues, then mix your other nutes, wait 15 minutes, then check/adjust the PH to about 6.2

Depending on your nutrients ratios, even tap water with 0.6 EC is ok to use, just cut the ferts dose by half or quarter.
Airstones are nice but if you grow in a nice aerated medium you won't need it so much
Basic rule is you add epsom or calmag first (if needed), basic ferts (such as A&B) and additives after (PK, etc)
After you mix each one in the water (always add each fert on its own, mix well and add the following) you ph the water.
If you grow in soil, 6.2-6.5 is best
If you grow in coco or hydro, 5.8-6.2 is best
Buy a cheap china ph pen, you won't need anything more than that.

I'd personally recommend a good ec meter and cheap ph drops, because the latter is always accurate.

Everything else has been covered in the previous posts

I like the China pen with added strips for good measure haha
The strips help you zone in and make sure china is not screwing with ya
But if you buy the cheap pen, save the 6.86 powder it comes with, every 3 weeks just dip it and calibrate it.
No fuss

If you're growing in soil, then EC/PPM is a much less important measurement. In coco or hydro it is important. I use tap water, and it's horrible, PPM's up to 1200, mostly Ca, Mg, Mn and Fe, so I don't need to add calmag, I did once, and it locked out N.