We bought a new trampoline cover last year when we covered our pool. The water was clear when we covered it. I know the mesh lets in water but when we opened the pool not only was the water murky but the liner seems to be stained along with the steps where the water was. We did all the normal things we usually do when we close except we have this new mesh winter cover. We've dumped a lot of chlorine in hoping to maybe work it loose at some point. What can it be and what can we do about it now?