I have a 12,500 gallon pool. Opened 1 week ago and it was cloudy. Cleared that, but now after 11lbs of shock my free chlorine is .2 and total chlorine is 2. I have taken apart the earth filter and cleaned the fingers. We drained a third of the pool and refilled it. I just added Phosfree and still no chlorine. All of my other levels are in range. Please help.