We've been in our house for a year and just discovered that we may have a plumbing issue where the backwash doesn't go to a sewer, but instead recirculates to our pool. We have a Hayward DE filter and a Starclear cartridge filter. The pool inspector didn't notice anything out of the ordinary last year, but when we hired him for pool school later, he was puzzled as to why we had the filter cartridge. Said it was overkill and didn't have an answer as to why some clean DE shot into the pool when he showed us how to backwash. We used the pool very little last year and only backwashed once, with the same result. This time dirty DE shot into the pool. We assumed we did something wrong in the backwash process, and forgot about it because we drained the pool shortly after (CYA was above 160 ppm when we inherited it).
We had the pool acid washed and the DE filter totally cleaned by a pool service company this spring in preparation for refilling the pool. The pool guy set the DE filter up for us, but also couldn't figure out why we had the cartridge filter. He never checked or cleaned it, and we didn't think anything of it or to check it ourselves, being pool newbies. So we backwashed a couple weeks ago after slamming the pool and black water shot into our pool this time. We called a third pool service company, who discovered the DE clogged filter cartridge when we told him what happened. He thinks there are 2 possibilities: either the original installer cheated and didn't run the backwash line to the sewer, or the pipe collapsed or clogged, so the cheaper solution was to install the cartridge to catch the backwashed DE. The problem is it's a huge mess to clean every time as I have to clean the filter and drain the filter container to get the floating DE out, which goes all over the ground, makes a mess that's hard to clean up, and poses a health hazard (I'm still trying to sweep it up and may try the shop vac).
The new pool guy mentioned getting a separator. I've been looking online and Hayward makes on that looks like we could swap for the cartridge filter. Does this seem doable? I've attached a picture of our set up, which may or may not help.