Cal-hypo is a form of chlorine often sold as bags of "shock." Since your CH (calcium hardness -- I think that is what you meant by CA) is 280, I assume that you have used some.

While you are battling cloudy water, you need to be maintaining your chlorine level at 15 as consistently as you can. And, you need to do so until you have clear water, you are losing no more than 1ppm of chlorine from sundown one evening until within two hours of sunrise the next day and you have a CC reading no higher than 0.5. At that time, I'd suggest keeping the chlorine high for one more day for additional insurance and then you need to make sure that you ALWAYS keep your chlorine level between 3-6 ALL the time. If you let it drop below that, you risk an algae bloom. If you haven't already done so, take a look at the Best Guess Chlorine Chart in my signature below for the connection between CYA levels and needed chlorine levels.