Since the shock and swim is cal-hypo, then you'd be better off returning it and getting a small container of stabilizer (also labeled conditioner, balancer, etc...but the active ingredient is cyanuric or isocyanuric acid). Somewhere in my mind I thought you said it was dichlor--must have confused you with another poster. Sorry!
Janet


)
) to monitor a CHANGE in cya, once there is a change I would say the cya has dissolved and we can use the "dunk" test or take another sample to pool store to get actual cya numbers.