I usually lose all my cya over the winter, but keep clear water. No algae upon opening in the spring. This year, I didn't lose it all. I closed with a cya reading probably around 40-45 and opened with it around 25 or 30. Who knows why it was different this year?

While you are fighting to clear your water, I'd leave your ph alone. Chlorine seems to be more effective when the ph is a little on the low side. Just make sure it doesn't drop any lower. At 7.2, you are fine. Then, you can bump it up a little when your water clears up.