At first glance the obvious thing you need to do is get your pH down to the low 7's. Chlorine loses effectiveness as pH gets higher--rather rapidly!

I have troubles with your volume calculation. Unless your pool averages 6' deep I don't see how you get 23,000 gallons. For example: If your pool is 4' deep, you'd have 16000 gallons. You'd have to have half the pool as a deep end of 8' to get 23,000 gallons. Volume = L x W x D x 7.48, where D is the water depth and 7.48 is the number of gallons per cubic foot.