Hi, I have a pool that is currently a chlorine pool. I'm am interested to converting to a SWG pool. And I have been told that when do this, I should change the filter sand. And I'm new to pools and would like some advise on this please. I have everything that I need to replace some internal parts to my sand filter now. But I don't want to change the sand now and have to change it again in the near future if possible. Thank you.