8.9 seems awfully high. What are you using to test your ph? If it's a color-coded result...check the colors under different lighting, and see if there's a difference. Or have someone else check the readings. (my wife's eyes are better than mine, for instance)
Tiz sooo much easier and cheaper adjusting the ph, than purchasing the distilled. And R/O does not change ph.
My well water comes out of the tap at 7.9 so I adjust with ph Down. (General Hydroponics) 1 gallon is $30.00. 1/4 tsp adjusts 1 gallon from 7.9 to 6.8ish. Usually I just mix 1 tsp:five gallon bucket, and the ladies are fine with that. Anyway...it breaks-down to just over 1 cent per gallon to adjust my ph, and I have had the same gallon for over two years.

Temperatures artifically alter the ph. That's why some ph pen calibration solutions have the temp : ph ratios. (don't like your ph...? Turn-on the A/C, lol) Testing ph at the same temps every day helps you to be consistent.
Rusty Trichome Reviewed by Rusty Trichome on . Water & Nutrient Probs Hey guys, I have recently had a few different issues, firstly the leafs were going yellow and the tips curling. I narrowed that down to the water in the reservoir evaporating and the nutrients remaining and being a little strong for the little fellas (young clones under a 600wHPS). To fix this problem i changed the water to plain tap water and let this go through the system (halo drip) overnight. Hopefully this cures this problem. Today i checked the ph of the water and its a shockingly Rating: 5