To test for general water quality characteristics such as pH and alkalinity, just get a simple swimming pool test kit and follow the directions. However, there are several factors that could cause these numbers to be out of recommended ranges. Along with testing the water a soil sample should be pulled from the bottom of the pond. From the water sample and soil sample analysis, recommendations for treatment can be made. I recommend you give me a call at 270-422-4958. Other environmental factors could be a cause of poor water quality. Correcting just your water now may not fix the problem tomorrow.