PH levels and RO?

okay so my tap water is usually around 8.5ph..

yeah i know but the assholes at the water plant add so much fluoride and god knows what else to make it a higher ph its supposedly heather for people to drink higher PH water

but after going out of my RO system it comes out at around 4..

now im pretty sure pure water is supposed to be 7

can someone explain to me wtf is going on here.. and yes I've changed all my filters. comes out at 000ppm

http://www.waterbenefitshealth.com/reverse-osmosis-water.html

An article about ro water, it says that most ro systems that don't have a remineralization system tend to be acidic, so low ph is pretty normal, hope it helps, happy growing

RO water pH is shifted soooo easily. The pH is essentially irrelevant. You have removed most ions that would have an opportunity to buffer the pH ( resisting it's pH change) You don't have buffers so the pH will shift wildly with a small addition of acid or base

PH changing is normal, like mentioned above, when filtered the water lacks a proper buffer. You should purchase a PH up and PH down kit, and maybe a decent PH reader, so you know exactly where your levels are at.