Yes SilverAvion, the boulders used for this pool are very large. Regarding Speakeasy's question, I did happen to be there the day this pool was being built. I heard stuff going on over there, but I soaked and spent time at/in the AZ Pool/Phoenix Pool all day. In the Afternoon some people came by and I asked them about what was going on and they told me some people were building a new pool. I did not see it till a couple of weeks later. I have not talked to anyone who have said that they were involved in the building of it. To get those big rocks out of there like SA said, it will take some strong backs. I have a genetic defect in one of my lower vertebrae so its not something I can do. SA, I have been going to DCHS since 1984, and in all of that time I have found in my measurements of the three main sources that they have remained at the same temp, 112 at the AZ Pool, 116 at the main source by the PCT, and 114 at the Crab Cooker. There have been numerous quakes during that time. When some day a really large quake occurs, it might change the temps. All of those sources are coming from really solid granite so it would take a lot to change them. I like you SA appreciate so much every time that I get to be at DCHS, and Deep Creek. Its always rewarding and inspiring