We have had to shock the pool once before and all went well. It took longer than I thought it would for the white cloudy water to clear, but we just kept filtering and eventually we had our sparkling pool back.
This last time, it seemed like everything was OK and there was no overnight drop and no color in the pool, so we just kept filtering and backwashing to clear the cloudy water, but it never got quite right. The only strange thing was that even on the first day that we had the pool at shock level, CC was only .5. The last time we shocked, CC was up for a while until no drop in overnight FC.
Anyway, a week later, we are back at it again. Last night I brought the shock level up higher than I thought it should be to 20 ppm instead of 16. And this morning, the CC was 1. This made me wonder if I should keep it up higher since last time at 16 ppm CC was never any higher than .5 during the entire shock process. I know that for mustard algae it is supposed to be higher?
What is mustard algae, and how would I know if I had it?? Should I keep my shock level higher than my normal 16?
Also - there seems to be rusty/orange colored stuff on the edges of the steps, etc. The same as last week before and during shocking.
CYA=40, TA= 90, FC=17.5 (this morning), pH=7.5 (last night before adding tons of bleach)
Thanks so much!
PS - would a picture help??