I got a nitro robotic pool cleaner, and noticed some old topics on it, but i didnt see one where someone had problems keeping the darn thing at the bottom and keeping it from floating to the top . does anyone that has one know how to resolve this? the manual says to clean the filter and get air out of it by moving it "side to side", which is pretty vague. dont know whether to completely submerge the thing and move it side to side or keep part of it above water and then move it side to side or what. does this happen with any other robotic cleaners and if so does anyone have any suggestions on how to solve this? Thank you in advance!