Take it easy... you are doing a good job already!

Opened it up this year to find a swamp that UFO come out of. Been hitting it with 6% chlorine everyday. Running pump 24/7 and added Muriatic acid last night.
You need to shock the pool to kill off that swamp but I don't think you are reaching a high enough Cl level. With zero CYA you need to get up to 10ppm based on Ben's Best Guess CYA Chart. I am estimating, based on the dimensions, that your volume is similar to my pool but you should confirm this. At 20K gallons you would need to add four gallons of 5.25% to bring the TC from 0ppm to 10ppm. With no CYA and with a 'swamp' you will have to check this frequently and keep the chlorine at or above 10ppm for the next few days. Run the pump 24/7 and backwash as needed.
The more I read the more confused I get; I don't even think I can get back to this forum to find out if it was answered. But I am going to give it a try. Here are my testing results from this morning:
FC 2ppm
CC .5ppm
TC 2-4ppm
pH 7.2
TA 340
Cal 280
CYA 0
I am running my spa aerator and I can't remember why. I remember reading something about the aerator lowering some reading but a can't remember which one. Thank you all for what you do. Maybe one of these days it will all come together. BJ
The spa aerator is running to help bring the TA (total alkalinity) down but I think the pH has to be lower for that to be effective. You can search for the posts but I believe somewhere between 6.8 and 7.2 is ideal. Another solution would be a partial drain/refill which may not be a bad solution. You may want to vacuum to waste for a while and just replace the displaced water with fresh.