Another wild guess (since that's all we can do without the test results Carl requested). It could also be dead algae floating in the pool. Intex filters are generally barely big enough to keep a clean pool clean. Once you get a mess, it can take a long time to clean stuff out of the water. If so, and if you have the capability to vacuum to "waste" it might be better to turn the pump off for a few hours so it can settle on the bottom. Then you could vacuum the dead algae out and top off the water.