My 6-year old is dying to swim and I've got green water even with high FC levels

[BigDave]

I can't suggest anything you're not already doing to clear the green but I do have a couple observations.

Save your FAS-DPD chlorine reagents by using an OTO testkit (yellow and red drops) for most of your frequent testing during this battle. The first couple times, do both FAS-DPD and OTO so you can get a read on the OTO color of high chlorine - it won't be on the comparator. Use the FAS-DPD once in a while to verify the OTO and, when you think the battle is won, to perform the overnight chlorine loss test.

As you note, filter quality could be a problem. See the Super Simple Recipie page for Amazon links to better filters. It's probably cheaper to buy better filters and remove some of the fine stuff than to buy chlorine to burn it all out.

High chlorine levels interefere with the pH test and bleach raises pH until it's done it's job. Don't adjust pH down (add acid) while the FC is above 10. If pH is below 7, however, you may consider moving it up with Borax.

The fact that the pool is consuming chlorine overnight and smells strongly of chlorine indicate that there's still a distance to go.

Stay the course, you will win this fight.
Good Luck, let us know how it's going.