yeah...that rm50 tuner juz lasted me for 1 year,and the warranty was 1 year...total bullocks
btw...classical guitar can use acoustic guitar tuner to tune?or is it the same?

It's best to get a good tuner like the Boss TU-80 so that you achieve right tuning.As for the nut remover,what's that?If you wanna remove the nut,place a piece of block on your frets,gently knock the nut.It should pop out easily.It's a little risky because it may peel off the finish beside the nut,so heat it.I use hairdryer to heat the glue under the nut.I heated my old kapok long enough last time that it just popped out without me knocking out the nut.