I would add some baking soda to raise the TA to about 60-70. The APP (Effects of adding) will help you with that. Today, also add about 10 ppm worth of stabilizer via the soak-soaking method. Let it soak and squeeze it all out after about 30 min. Immediately add some chlorine. Don't be shy, especially with a party coming. You are on the verge (if not already) of an algae bloom. I would increase the FC to "10" today and try to keep it that way until tonight. Tomorrow morning test the FC again but keep it steady at a healthy 5-6 ppm.
After the party, you might increase the FC to 10 again and do an
Overnight Chlorine Loss Test to ensure you don't have algae trying to grow.