Hi Kresse;

1. Stay away from that store, far, far away!
2. Forget about ammonia - with a high stable chlorine level, that is NOT the issue.
3. Do NOT worry about alkalinity yet.
4. Turn the pump off for 24 hours, and lets see of the calcium cloud will settle out.
5. Tell us what sort of pool you have: vinyl, concrete, fiberglass, etc
6. If your heater is ON, turn it OFF, and leave it off till this is resolved.
7. Call your pool store, and see if they have this EXACT product in stock:
GLB Pool & Spa Products 71408 1-Quart Drop n' Vac Pool Water Clarifier @ Amazon
If not, order it from that link. You may not need it, but there's a fair chance you will, and it will take a few days to arrive. If you are able to get it . . . do NOT use it without further advice! If your store has it, you can wait to see if you'll need it. But do NOT listen to their advice!