Midcurrent.com Covers a Very Important Chapter
If you don't know of Midcurrent.com, you should take a look at it when you get a chance. I highlighted this all inclusive fly fishing media site in my book Modern Trout Fishing. Midcurrent covers tactics, techniques, strategy, flies and fly tying, art and film, science, bio pieces, event, conservation, interviews, travel, gear, and the whole gamut of little pieces that make up this game we play.
They recently did an excerpt from my last book - Finding Trout in All Conditions - focusing on that chapter dealing with pH levels on rivers and the impact it has on fishing (I cover specific conductance and dissolved oxygen in the same chapter). pH is an often neglected factor when it comes to external influences. This can be a mistake at times. Acidity and alkalinity are life and death to trout and the waters they possess. I urge folks to analyze USGS stream gauges containing real-time information online. I am not a big fan of pH strips and self contained pH monitors, but one of the commenters who viewed the excerpt recommends pH strips that can be used streamside. That fly fisher's opinion on the matter is just as relevant as mine. read it all at http://midcurrent.com/science/reading-the-gauges-ph-levels/
And take a look at the rest of the site. You can learn a lot at Midcurrent.