Not sure if partially in your case your ever set the level properly after cleaning and then come back the next day and the water level is half way down in the body barely producing because it removed all the waste and then having to adjust the water again only to the raise and later have and over flow after feeding
Yeah, I have certainly seen behavior like this. Once it I get it stabilized, it'll run for weeks with no issue before I inevitably change something in the system and have to readjust. The next time I destabilize the system, I'll have to try your approach

