I have a 15' AGP with a 2500gph filter pump. I'm thinking about going to saltwater because of the chlorine shortage. I kind of wanted to upgrade my pump/filter to a sand filter at the same time that I went to saltwater. With SW generators running $150+ I thought it would be possible. But I'm only seeing pumps around 2150gph with saltwater on them in my price range. My question is how does sand filter vs catridge filter compare as far as gph efficiency? I don't want to settle for less gph just to go with sand if I can be just as effective with my 2500gph cartridge and adding a stand-alone SWG. I hope this question makes sense. Thanks in advance.