Has anyone checked the ph of the water coming out of the pitcher?

I have a pH meter that I use for wine making. It has a resolution of 0.01 pH, and an accuracy of +/- 0.01. I calibrate it before every use so I am confident of the reading. The pH of the water form the pitcher when new was just over 9 - about 9.03. After 4 months of use with the same filter is is now reading about 8.79. We use two to three pitchers of water per day.

I have been using this pitcher for about a week and have just noticed that I have carbon particles in my water. Anyone else? Why is this?

The carbon particles are just residue from the filter, it took me three or more rinses before I felt it was clear enough to drink the water. The Stage-5 Carbon filter is a GAC (granular activated carbon) filter so it contains loose carbon media. When water runs through a new carbon filter, it is common for the filter to release a small amount of loose black carbon fines. Just continue to rinse until it is clear enough to make you fill comfortable. It's no big deal. Just check to make sure that the filter cartridge isn't cracked damaged from shipping.