Flushing

In flushing a plant that may display issues of ph or other insufficiencies is it important that the water is ph correct? The water from my tap is on the alkaline side...7.5.

depending on the ph of the soil in the first place you want the ph of the water to be as near to 6.5 as you can get in a soil grow.

I use soil, and I always flush at 6.5, but others have told me that soil buffers pH and that I can flush plants with water straight out the tap

If you have insufficiencies, why would you want to flush and make the situation worse? That doesn't make sense.

Flush if you have too much of something, not if you have too little.

Wet

Yes, I believe that it's important to have the PH correct. If you were to flush with 7.5, thoroughly, your soil PH would be at 7.5 for awhile, making nutes less accessible, especially Mag and Calcium. Yeah, your soil will likely buffer it down, but who knows how long that could take, days, or weeks, in which time, the plants would be lacking. Idk about you, but I don't like that idea.

Its a must that your water be balanced ALL the time, especially during a flush. The soil will tend to take on the ph of the water it's given, if watered correctly, and that's the easiest way to control your ph, is to make damn sure your water is always balanced.

Another consideration: Once you balance your water, it doesnt stay at that ph for more than about 48 hours before its starts to drift back to its original ph. This seems to be more the case with alkali water. (straight from the tap)

Also, make sure your water isn't cold when you flush, the whole idea of the flush is to void the things you don't want, warm water will make it so you don't need as much water for your flush to be effective. Let the plant sit for about a half hour between flush sessions, one time to loosen it all up, and a final flush to rid the material.

I appreciate the input. The plants are at the end of their lives and I have one plant that has slipped to the acidic side and it's shows. The runoff on the others is fine.
I believe it is probably too late to correct the acidic one seeing there are only a couple of weeks left. Thanks again.