I'm having the exact same problem. Had the auto weekly timer (Active 20) set to every 3 days and still a lot of debri. Changed to every 2 days and the same thing. Changed to every day and the same thing. Then I noticed on this exact thread how it appears a recent batch of Active 20s is having issues with a 15-30 minute cycle so I decided to watch the cleaner last weekend. It's running a full cycle (2 hours) but it's getting stuck on the maindrains quite often. I would check it every 30-60 mins and about half the time it was stuck on a maindrain (note the maindrains were shut off too). Couldn't find a lot of info while doing research but solutions I've found were:I have had my S-200 for a couple of months now and really love it except for an issue I've been noticing lately. It seems to get hung up on my drain covers in the deep end some of the time and can't get itself off. It must not happen all the time because when I run it at night it'll end up back in the shallow end most of the time. Yesterday I was out by the pool while it was running a cycle and noticed it stuck. I waited to see if it could work itself off but after 15 mins I had to pull the cord to drag it off the cover. The filter wasn't running when this happened so it's just getting stuck on top of it. Does anyone else have this issue or know a workaround for it?
-decrease or turn off maindrain(s) (didn't work for me and I think having to shut the main drain off kind of defeats the purpse of an auto cleaner w/ timer... i try to run my pump over night but forget to shut it off or on)
-Polaris uni-cover - $61 (Polaris 5820 White Unibridge UniCover AV Main Drain Cover Inground Pool Cleaner - Walmart.com)
-I would see if any cheaper (knock off) versions of the unicover exist
-main drain clip - $19 (Main Drain Clip-On - Pool Maintenance Simplified)
-contacting Maytronics to send you (I believe for free) an impeller cover with an added "hood" that diverts the water back and provides a bit of forward "propulsion. (may or may not work)
I went w/ the main drain clips. you're supposed to have 2 per drain (in the shape of a plus sign for robots) but I don't see how why 1 wouldn't work so figured I'd start there. I actually just found out about the Maytronic's fix so if I could back in time I would have started with Maytronics and if that didn't work then searched for a unicover equivalent cheaper than the main drain clips. if no such equivalent existed then go with the clips. Hope this helps!