I experienced a very similar situation but I wasn't careful enough to pour pre-mixed soda ash into the pool; I added 10 pounds in different spots of the pool in chuncks of 1 pound
Bottom line, my pool has been Milky White for the last 4 days and after several visits to pool stores and following the instructions, I'm still in the same situation.
The last visit was to 2 different pool stores (to compare criteria) and they both said the same: Chlorine is not working as it's too saturated.
1) empty 1-foot of water from the top and re-fill (waste)
2) Don't add chlorine until water clears up.
These are my readings before emptying the poolin parenthesis, the status as per Leslie's). All units in ppm (unless noted)
CH: 120 (Low)
pH: 7.6 (no dimensions)
TDS (Total Dissolved Solids) 650
I can't see the bottom so I have no idea if there are residuals particles.
You can notice only the fist step of the stair is visible, beyond that (2 more steps), only the white NADA!
Last night, I let pump run overnight after re-filling the pool (I don't have the new readings as I have to take a new sample and go to the pool store for it.) and still milky cloudy water.
Recommendations I've read in different forums go from using FLOC, checking the filter, and the most drastic is, emptying the pool completely and re-filling.
Help is highly appreciated
PS: New member, 3 year pool owner , ergo, very limited experience. Thank you in advance for your patience