We live South Jersey, it just snowed yesterday 9 April 2016. A little early for opening the pool but this is when i start thinking about it.
Hopfully this isn't OBE.
There are a number good ways to prevent a Green pool when you finally remove the safety cover, but the best one I know of I learned several years ago while standing in line at the pool store waiting to buy chemicals, etc.
The simple method I was told about, and it works, is to cover the safety cover with Black Plastic available at most home stores. The plastic keeps the Sun's Rays from penetrating and aiding algae growth. It also keeps a lot of other garbage (pollen, etc.) out. I put a small pump in the middle to pump off rain water that will accumulate. My pool is in ground so I use some extra paving blocks I have to weigh it down on the patio around the pool.
When I'm ready to open in mid-May, I pull the plastic off on to the lawn, hose it off and store it away for next year.
Since I started doing this my pool water has been clean and clear every year.