Flush with reg tap water?

I'm growing some girls in 5 gallon bags. It's about time to flush again. I have been flushing with plain ph water. That was when they were in 3 gallon bags. Now that I've transplanted into the bigger containers, it's gonna take 3x's the amount of water. Can I flush without ph-ing the water then hit 'em with ph mild nutrient solution? Or will using the non-ph water fuck up the soil even though I end the flushing with ph water?

I would like to flush the gals in my shower using the detachable shower head. The water where I live is usually between 8.4 - 8.7.

If it will fuck 'em up, I don't want any part of it.

I'd PH that water down to at least 7.0. You can use distilled white vinegar to PH down if you're just gonna flush with it, then use your good PH down stuff for the final flush only. =)

I usually let the water set out over night to evaporate chlorine and what-not. Can I just ph the tap water without letting it sit? I only have one 5 gallon bucket I use for water. That might be enough for one plant. I got a few... I will get more buckets soon, but, until then, will I be OK not letting the water set out?

After more research, I hear that ph tap water would be ok. Not the best option, but, it will work with minimal effect to the plants if any.