You want to buy 94% or higher cyanuric acid (which is sometimes called stabilizer or conditioner). If it is at least 94% cyanuric acid it will be fine. Folks on this site say Walmart sells HTH brand that is 100% but my Walmart does not -- if yours does, you are in great shape. There are other options for getting CYA into a pool, so if you have any question about the exact thing you want to add to save the drive, post specifics off the label and people here will tell if it is okay. Good luck, and Welcome!