Hey Shub;

Some of the contributors and I have been discussing high Cl + high CYA operation, and there is a better method for testing pH for you. You'll need a gallon of distilled water, a measuring cup, and your pH kit. Simply mix pool water 1:2 with distilled water: 1/4 pool water & 1/2 cup distilled water in a glass measuring cup, stir, and test.

You don't report pH (for obvious reasons) but I'm guessing your pH had climbed quite a bit, which affects measured alkalinity levels in its turn. If you keep lowering pH to below 7.0, and then letting it rise before lowering again, you will lower your TA over time.

Regarding chlorine consumption - it may, or may not be unusual to lose 5 ppm per day.

However, cloudy water in the AM after a clear PM, has always -- in my experience with commercial pools -- been associated with either incipient algae (rarely) or heavy bather load (lotion, urine, sweat) with inadequate chlorination.

So let me ask some more questions and clarifications:
+ your pool is about 17K gallons
+ you mention lots of kids on the deck: how many users in the pool daily?
+ are your users heavy users of lotion or sunscreen?
+ do you have any 'slip and dippers' -- ie, lotion up, lay out, rinse off, repeat ? (This creates heavy chlorine demand.)
+ is your pool a long way from the bathroom and / or have you forbidden wet swimmers in the house? (= pees in the pool)
+ are any of your users competitive swimmers? (USS swimmers are accustomed to pee in the pool. Really. It's universal.)
+ is your pump on a timer? What are the settings?