I have a 18ft x4ft above ground pool and the water is green. I have kept tablets in the pool and also I have kept the ph right in it. I added some chemical for metal and nothing seems to be working to get rid of the green. I am at wits ends with trying to get it back clear. When I filled it up it was clear and stayed that way until the water got warm and rain water got in the pool. I don’t know what else to do . Please help me get rid of the green and back to sparkling clear water.