Hey, I am new to quadcopters, and have and FPV Factory Mariner. Internally, it is essentially a DJI phantom. It uses the NAZA system and the controls, lights, etc. are all identical to the phantom. The only real difference is that the Mariner is waterproof. Here is the problem that I have been having. It won't hover well. If I let off of the sticks, it moves all over the place in a fairly large area (at least it seems large to me). It will suddenly drop or shoot up about roughly 20 feet and it it will pitch and roll at least 20 feet horizontally. A few times it has also suddenly developed a mind of its own and gone plowing off rapidly even though I wasn't moving the sticks (every time that it has done that, it went down while moving horizontally, and one time it crashed as a result, fortunately it was in water so there wasn't any damage). I'm flying it in GPS mode, I have the factory recommended props on it and they are on correctly, I calibrated the compass before flying it, and it had full GPS signal. There was some wind, but it was by no means a strong wind, and I have seen videos of these things holding a very stable position in extremely strong winds. Also, I had it in the home lock mode where my left is always left and my right is always right, if that matters. Is there something wrong with my quadcopter, or am I doing something wrong, or am I just expecting too much of it? I read a lot about these and watched tons of youtube videos before buying it, and I really expected a lot more stability out of it. Thanks for the help!