I went to my local brew supply and found that there pH strips are in the range of 2.8 - 4.5, which isn't really ideal for kombucha considering the target is 3. How do you test acidity and where do you get your strips, if you do buy them?
I used to use test strips sourced from farm store or a big box store, for water maybe, I think they ranged 0-14, but now own a meter like this...http://pages.ebay.com/link/?nav=item.view&id=281076449503 (no affiliation to this seller, but mine is exactly like this)
All of the guess work caused by color matching is taken out of the equation and you can source the calibration chemicals online also. The cost of strips will quickly add up to a pH meter.