I just purchased a new Intex Sand Filter with 12 inch tank from Amazon. My pool is a Coleman 18 *48 we hooked it up and its running great for a while then it just starts losing pressure I guess. It stops blowing as hard into the pool. The water was drained from the pool and refilled with clean water. There was some small amounts of algea left in it which we are trying to remove. The water is clear so we cant figure out what would be causing the pump to loose power like its doing. I can backwash and then it starts working great for a short amount of time.