Cloudy pool water using ozonator

We have a 30,000 gallon in ground pool. We have used an ionizer and ozonator for sanitation for over 20 years and the pool stays crystal clear. However this year when we opened the pool we cannot get it clear. It is blue but very cloudy (you can see the bottom in the shallow end, but not the deep end). We have taken water samples to our pool store and everything is balanced. The sand has been changed and the pump, ozonator and ionizer are all working properly and run 24/7. We have flocked it, but that did not help. Any suggestions?