Don't know what to do first.. I just read somewhere on the forum that before shocking you have to raise the ph up to 7.5 ppm , mine is at 7.2 ppm , or should I increase the alkalinity first like the guy at Leslie'S said by adding 24 Lb of Alkalinity Up?.. It seems like a lot ..I also read that it should be introduced slowly and at the pool solution site I read that if you have a vinyl liner it's not that big of a deal if your Ph does not go up and down ( I found a reading from Leslie that my husband did and the PH was the same 1 week ago) I know I HAVE to shock tonight no matter what.. CAN I INCREASE PH BY ADDING BORAX tonight right before shocking ??will it work quickly? AND MOST IMPORTANT..What do I shock with?? I need something from wal mart which is still open now. Since I have a reading of CYA 20 ppm is it a good idea to find some kind of shock treatment with added cyanuric acid?? Pls .. pls HELP.. I don't want my husband to return to a pool full of green algae nor do I want to break our tight buget by buying the wrong stuff that will result in more cost afterwords to clean up the mess..