New to the site. Don't know if I am asking this question in the right place but here goes. I'm a rookie at below ground pools but have been able to figure things out so far. My current problem is getting my pool crystal clear. Yesterday, I noticed after asking my wife to turn on the pump. That clouds burst from my two returns in the shallow end of the pool. Pretty sure I have a filter problem. I bought the pool with the house so I don't know how old the filter is. It could be theoriginal (aka over 20 yrs old). It is a Heyward Sand Filter. Pump is working fine. Just looking where to start trouble shooting....or do I just replace the old filter?

Any thoughts where to start?