Ok. Well adding DE to it will help it filter better but you will probably need to back wash more often.
You need to perform the shock process. And because you had metal staining problems get the pH lowered before you start the shock process as you won't be able to accurately measure the pH.
You need to perform the shock process. And because you had metal staining problems get the pH lowered before you start the shock process as you won't be able to accurately measure the pH.