Did you use di-chlor powder for your chlorine? That explains the high CYA. It's not BAD, but I would only use liquid chlorine or bleach from here on in. No more powder or tablet chlorine.

If your pH is accurate, with a vinyl pool you need to raise it IMMEDIATELY so your liner isn't damaged. Add a full box of 20 Mule Team Borax (not pH Up! or any soda ash). Wait an hour or two and measure pH again. Keep it up until pH is at least over 7.0. Then aerate your water because your T/A will rise when you do this. Aerating will raise pH without raising T/A further.

You did not post hardness. While it's not needed for vinyl pools, if it's very high (like 500ppm) it could make your water cloudy--milky. Otherwise it's probably dead algae.

FC of 40 could bleach your liner but otherwise won't hurt it. You really only need to keep FC at 20 to kill everything and get rid of your FC. I'm guess "By 5" meant you used 25 ml of water and every 5 drops is 1 ppm. Don't waste your chemicals. Use 10 ml of water and 2 drops is 1 ppm. You don't need more precision than that.

All this is in addition to Dave's sound advice. Watch your pump pressure: When it goes up 5 lbs, back wash your sand filter. You could try adding a little DE powder to your filter through your skimmer 1/4 to 1/3 cup should be enough. DE's cheap--a 10lb box is less than $10 and lasts a sand filter owner years. Also skimmer "socks" pull out a lot of fine junk like pollen before it even gets to your filter.

Good luck!