Does the water look worse today?
From the pictures, it looks like the pool was looking better yesterday.
In any case, I would raise the TA to about 90 to help prevent the pH from going too low.
I think it looks about the same. I can barely make out the bottom step, which is what it looked like yesterday too. Yesterday was pretty sunny, and today is a little overcast, maybe that explains the difference you're seeing in the pictures.
Would you recommend raising the TA with soda ash or baking soda? It seems like I could raise the pH and the TA at the same time with soda ash.
From what I can gather 6 ounces of soda ash will raise the pH 0.2 and the TA by 5ppm per 10,000 gallons.
I would need 6x2.25=13.5 ounces to raise the pH by 0.2 and TA by 5ppm.
I'm thinking: start by adding 27 ounces of soda ash to hopefully raise it to 7.0 or so pH and 80 TA. Check after an hour and adjust.
You're also at a point where after getting the FC to hold last night, the next 24-48 hours will require vigilance to try and maintain the FC of 12 as consistently as you can. Large drops of FC (like 4 or below earlier) can set you back a bit. Hang in there!
Thank you! I'm going out to check again shortly.