Hi all! My husband and I are new pool owners. We purchased a home a year ago with an unground pool. The previous owners had a pool service guy who came out and maintained their pool. We continued to use the same serviceman until here recently because I noticed that he was only ever adding chlorine to our pool. I took a sample of water to a pool supply place in town and they said our pool had a cyanic acid reading of 120. When I asked our serviceman about this he said everything else read fine so not to worry. We have since stopped using the pool guy and are now draining some water from our pool to get the CYA corrected. My first question is how do I determine how many gallons of water are in my pool. we have a kidney shaped pool with a half circle hot tub attached. The previous owners were not sure and the pool guy said about 25K to 28K. I used an only calculator using this measurement of our pool and it says 18,711 with out the hot tub! I am so LOST! Please help me. I have also ordered the Taylor Technologies test kit and it should be here today so I can get our pool back in shape. Another question I have is how much water should I drain from the pool to lower the CYA. We have already drained a little over a foot. Thanks to all who are willing to help me.