Adding 20 lbs of either chem is enough to make a cloudy mess out of your pool, but adding 20lbs of each almost certainly did it. However, even if you don't have algae right now, you will soon if you don't raise your chlorine levels. With a CYA of 75, you should never let your chlorine levels get below 5 ppm, or you are inviting algae to get started.

Is your filter pressure rising at all? And since this is a vinyl-lined pool, just for future reference, you don't need the calcium, no matter what the pool store says. It is needed in concrete/plaster pools to keep the water from leaching the calcium out of the finish, but in a vinyl pool, it's not necessary....