Is the CYA granules or liquid? You would not use this if you are going to follow the dichlor method in that Temp Pool link.
You certainly should get some FC in the pool ASAP. Then add the CYA in a sock hanging in front of a return (assuming it is granules).
Tomorrow you can lower the pH and maintain the FC.
You certainly should get some FC in the pool ASAP. Then add the CYA in a sock hanging in front of a return (assuming it is granules).
Tomorrow you can lower the pH and maintain the FC.