One tweak ----- A clarifier will make small particles clump into bigger particles so the filter can remove them more efficiently. A floc makes these particles clump into much bigger particles that will settle to the bottom of the pool and are then vacummed to waste (not possible with cartridge filters and some DE filters). So, if shocking and holding it at the high cl level for a few days (along with running the pump 24/7 as Jan said) doesn't do the trick, you might try a clarifier, not a floc. (But, I wouldn't be in a hurry to try it. Give the high chlorine and just the filtration system on your pool time to handle it.

BTW -- It usually isn't a good idea to add a bunch of stuff to try and fix a problem in a pool. Pool stores love to sell you tons of stuff and pool owners who are having trouble are usually quite impatient and frustrated and willing to try anything the pool store suggests. Usually, nothing more than chlorine and patience will solve many problems.

Welcome to the forum!