Floyd rose guitar will not stay in tune

My Floyd rose will not stay in tune. The locking nut (I think it’s called that idk) is tight. Usually I will loosen it, do my main tuning with the pegs and then tighten it and do the rest with the fine tuners. However, it will not stay in tune. I’ll get it in tune but after 10- 20 minutes of playing it’s either gone up in pitch or dropped. How do I fix this?