There is a company in Colorodo that does water testing. It's called Fisheries Technology Associates. Here is a page from their website regarding a standard water test. They will also interpret for an additional fee and of course they do consulting:
http://www.ftai.com/standard.htm I too raise trout in a small pond but at only 900 feet! One problem you have is your water will hold less oxygen at such a high altitude. This causes more problems for you than it would for me if your water warms up as in the past drought as in warmer water there is even less capacity to hold water.
As far as the brown foam, it could be related to iron, but I'm just guessing. The stuff that floats up sounds like some type of algae which is not necessarily that bad. I have a problem with in in early spring but it completely disappears later. I also add a bacteria know as Aquatron from Keeton Industries (also in Colorodo) that is supposed to compete with the algae for nutrients.
Is you fish growth is good, and do your fish feed well? If so you should be O.K.
