With a SWG, you need to maintain salt and CYA levels in the water. Backwashing will remove both of these elements which will need to be replaced. A large DE filter is not as bad so you won't be replacing salt and CYA as much as you would a sand filter. Also, when you are backwashing, keep in mind that the salt level of the water is higher than normal so you may not want to backwash on to your lawn or landscaping. But if you have a backwash drain to the sewer system, this will not be a problem.