You may add muriatic acid if you like. Try 1 quart at time, poured directly into the pool near a return, preferably in the deep end. Wear gloves, glasses, and watch out for the fumes. Wait a day, before adding more.

DO add bleach, 4 gallons per evening, till your pool is clear OR till your chlorine level is HIGH in the AM (orange on an OTO tester). Do NOT let it get to zero again

Do NOT add anything else.

Ben