Total Chlorine is the free chlorine plus the combined chlorine. The first numbers you posted were :
Tot chlorine 7.3
Free Chlorine 6.1

Which leaves you with 1.2 combined chlorine, which means that you are fighting something in your water. Without a test that tests for combined chlorine it is ok to just bring your levels up to shock - I would try to bring it up to 20ppms. You can tell that you don't have anything fighting your chlorine when the chlorine holds overnight.

I told you to point your return eyes up so that you can aerate your water, because as long as your ph is low, you can lower your alkalinity this way, and your alk is way to high - it should be 80 to 125 in a vinyl liner pool and not higher than 180.

Just keep adding the chlorine - your pool will clear. Every time it goes down at all, add it back to 20ppms.