Why is my pool so dirty!!!

[chem geek]

Just wanted to report in. I chose to raise the clorine level to 35 ppm for 60 hours with pump running. I brushed each day. It has been two days since I stopped brushing and it still looks good. If I dont need to brush tomorrow I will know that I have won the battle. I am going to add Borax to the pool next week to see if I can level off the acid usage and provide some algecide benefits as well. I hope it works! Thanks for help.

Great news about your pool getting cleared! You'll know that you've gotten all the algae if your FC level holds up overnight (or not in sunlight) and you have no (or < 0.5 ppm) CC. The 35 ppm probably worked because you started out at a little lower pH and, most importantly, the temperatures are cooler now so the algae isn't growing as fast. At any rate, it's good to know.

Don't forget to lower your TA to 90 or even 80 as that will also help. Follow the procedure at this post to lower your TA.

Your biggest problem now will be how to get your FC level back down if there isn't any sun to break it down, but technically with a CYA of 70 ppm and an FC of 35 ppm, the disinfecting (and oxidizing) chlorine level is at the same level as it would be if you had 1.0 ppm FC with no CYA. Though I would be confident enough to actually swim in such water, I'm a nutty chem geek. There's always the possibility that the chlorine bound to CYA does something nasty we don't know about (though it doesn't show up in ORP sensors, doesn't seem to kill any bugs, doesn't seem to oxidize anything, or do anything else that is detectable...). I did find that one can use hydrogen peroxide to lower chlorine levels rather than using sodium thiosulfate, so that was good news.

Richard