Okay so you can hold FC for a little bit so that is good to know.
It is time for a battle. Here are your tools for the battle against the green monster:
-chlorine and lots of it! Do your best to get and keep the FC at SLAM/shock level as seen in this chart:
Chlorine / CYA Chart - Trouble Free Pool
-CYA aka stabilizer-You can buy this at Walmart or Lowes-Get the powder kind. Do NOT follow the directions on the bottle. Put it in a sock or panty hose. Hang it in front of the return off a broom handle or such. You want to add enough to get it to 20 at this time.
What you are smelling is the chlorine doing it's thing----------killing the nasty stuff!! This is a good thing for now. Once you get done with the SLAM you will not smell that again.
Now what is a SLAM??? Here is the link to it:
SLAM - Shock Level and Maintain - Trouble Free Pool
There are many parts of a SLAM that are very important:
-run filter 24/7
-brush pool at least once a day-this helps get the yucky stuff up and into the water for the chlorine and filter to kill and get out of the water.
-MAINTAIN the FC level at your SLAM level for your CYA as much as possible. If there is no one home during the day just do the best you can. When you are home do a FC check every hour and add as needed to get the FC to SLAM level.
I do see your water is starting to trend to blue so that is good. It will get better and better every day. Taking a pic each day is a good idea as it shows you the progress that your eyes can't always see.
Kim