Can Phenol Red be used to test ph levels in drinking water? I am on a well that has a soda ash feeder to increase the ph to acceptable levels. I used Phenol Red to test the water coming out of our faucets and got a reading of 7.6.

When I was in the water treatment company where I buy the soda ash, I mentioned this to the owner who said that's not a reliable test. He said that Phenol Red is for use with highly chlorinated (e.g. pool) water and will produce an incorrect (e.g. high) ph reading in unchlorinated water. He said I need to test with Bromothymol Blue.

My concern is that Bromothymol Blue has a test range that maxes out at 7.6. If my ph was higher than that, I'd (possibly) never know. Plus, I've seen plenty of (supposed) expert information online that says Phenol Red can be used for drinking water.

Do any of the experts here have an opinion? Many thanks.