I recently refurbished my 280 and also put a new feed hose on it. It is now doing a great job of cleaning about 75% of the pool but almost never goes into the shallow end. One tip I read about was to move the Polaris cleaner float further toward the front of the unit. This helped a little but still not enough. The backup valve seems to be working properly but the cleaner seems to continually make left turns pretty much keeping it out of the shallow end. Any thoughts on what els might be wrong?