Short, quick hits: drink enough, but not too much. Thinking back to the end of June and my ride, I started out in the hole - but then I went WAY over the top and started taking in too much. In my efforts to stave off dehydration, I went the other way. Thankfully, I did supplement electrolytes during that "adventure", but I still took in far more than I should have. Reinforcing that is a good, well-written article about hydration that I found on Hammer Nutrition's website.
Disclaimer: I don't work for Hammer Nutrition, but I've been using their stuff for years (when I can afford it), and have a pretty high opinion of their thinking, philosophy, etc. BUT, they are a "company" with employees that are trying to make ends meet. Refreshingly, this article is not terribly "sales-y" in nature. Facts, numbers, advice, and cited references abound - but, yeah, they are going to mention one or two of their products, just like any company will. I still recommend reading it if you are still riding and training in the high heat we've had around here lately.
You can find the article here.
Thanks for reading! Stay tuned for another 200+ kilometer ride report, coming next week.
Stay cool - ride safe.