[EDIT] The following assumes no automated dosing. I missed reading that there is an SWG which should maintain chlorine levels automatically. [END-EDIT]
If you've got full sun, then with a CYA of 65 you may lose around 35% of the FC each day (is that how much you lose over 24 hours?). Even if you raised it to 20 ppm FC, it would drop...
20 ... 13 ... 8.5 ... 5.5 ... 3.6 ... 2.3 ... 1.5 ... 1.0 ... 0.6 ... 0.4 ... 0.3
and usually when it gets very low it may go away completely and not just be a proportional loss. By shocking higher (say to 26 ppm) one can usually go for almost 7 days, but 10 days is a stretch unless you cover the pool with an opaque pool cover.
You might consider having Trichlor in a floating feeder, though that usually doesn't last for 10 days, but if you put it on the slowest release setting it might help for those last days.
Another thing you can do is to add Polyquat 60 in a larger initial dose. That also won't last for too long, but it will still have some remaining even after one week. You'll need to dose with it first, then shock with chlorine, then bring the chlorine back up after a day or two since some of the Polyquat will react with the chlorine.