Okay so I was having a pool party and all went wrong. I brushed the whole pool and the bottom had white "dust" that would stir up with the brush. The water got a little hazy and UPS brought me a bag of DE to try out in the sand filter. I added a 1/3 cup to the filter basket with no rise in pump pressure. Soon after, 5 kids, 4 adults, and a labrador dog are having a great time in the pool. I had the heater cranking for the whole day so the water was about 90 degrees by evening and the pool turned white! I don't know if it's the DE, or the bottom being stirred up, or what.
Here are my numbers I just took: