Your "drops kit" might be good to check PH. You should check it now before adding any bleach or chlorine. We need your PH to be about 7.2 before starting a SLAM with higher bleach content. PH is lowered with muriatic acid, or raised in one of three ways: borax, soda ash, and aeration.
I suspect your drops test kit will only test chlorine up to the level "5" right? That's our problem with some of those smaller store kits.