I would sell all the chemicals. You're off to a good start managing your water and you will probably neverneed them.

Secondly, get your chlorine levels up to around 3-5ppm and keep them there. If you test at 3ppm in the evening and most of it is gone by morning, you'll need to shock. If it decreases by 1ppm or so overnight, then simply maintain it in the 3-5ppm range but don't let it get back to 0.