Dude - great questions.
I haven't had the privilege of using AN's pH Perfect, but I want to after reading this review - and it sounds like it answers some of your questions. Of course, I have no idea who wrote it, so I guess you have to take it with a grain of salt.
Personally, I've used AN for my MMJ for some time now and I love it, and I expect that pH Perfect is as great as some are saying.
Good luck!
Here's the link:
http://www.advancednutrientsx.com/advanced-nutrients-ph-perfect-review.html
Its probably fair to say that all fertilizers effect pH as soon as they are mixed with water, and the Advanced Nutrients pH Perfect nutrients are no different except it doesnt matter what your pH reading is it will always end up available to the plant because of the new smart release technology. The nutrient couldnt possibly know what type of system it was in so the pH would read whatever the local water was after a nutrient was added, leading us to believe that the growers that have checked their pH immediately after mixing have seen a lucky result.
What Did We Find Out About Advanced Nutrients pH Perfect?
Example: One grower using the 3 part Advanced Nutrients pH Perfect in a hydro system with RO (Reverse Osmossis) water checked his pH after mixing the tank & said the pH was perfect at 5.8 without the addition of pH up or down. Another grower using the same 3 part in soil with local tap water checked his pH after mixing the tank & said the pH was perfect at 6.5 without addition of pH adjusters.
So how did the nutrient know?
It didnt - its that old thing of nutrients changing the pH when mixed with water & the Advanced Nutrients pH Perfect would have worked any way even with a reading of 7.5 the nutrients will still all be available to the plant as and when they are needed. So what will my meters read? Whatever the water is with some nutrient added which could be anything.
Did Advanced Nutrients pH Perfect work?
Yes, very very well is the short answer.
The longer answer is we tried & tested the pH ppm Perfect nutrients at 4ml per litre from Advanced Nutrients on different plants & systems with great results without any pH adjustment or EC metering and the worst thing that happened was very minor tip burn while it seemed to be settling in, even with additions of Bud Blood & Big Bud.
We are very pleased to announce that our growers have grown crops full term over the last 4 or 5 months on total Advanced Nutrients Sensi Grow and Bloom & Grow Micro Blooms new dilution formulations from Advanced Nutrients, with outstanding results finishing up to 1 wk early. Regular tank changes, up to every 4 days are preferable but our display systems have had none or very few.