Get a tuner and tune it yourself is better. Transport a guzheng to people for tuning not "ma-fan" meh? Good news no need to buy tuner if you use android phone. There are plenty of tuners there. I believe there tuners on mac/iphone too but I am not a mac user to comment.
Some 5 years ago I bought a tuner off the shelf and it showed me ABCD. These type of tuner is no use for GZ. From string 1 to 21 you have 5 - D notes. You will not know which D note for the string. You need a tuner that shows the frequency. You can get this type of tuner on android apps.
String #1 for GZ is the highest note. It is the thinnest string. GZ colored (green) strings is call note 5. The highest note 5 for GZ is string #3. It is tuned to 440Htz. Going down another 5 strings to the next colored string is the middle note 5 or string number #8. It is tuned to 220Htz. Next colored string is 110Htz and the last one is 55Htz. With the frequency as a guide you will know how much to screw the tuning peg. Any string between the middle 5 and upper 5 note had to be in the range of 220-440Htz.
The alphabetic note guide is Note 1 = D, Note 2 = E, Note 3 = F#, Note 5 = A, Note 6 = B. If you tune with this guide (without frequency) you can snap some strings tuning them too tight. It was my first experience.
String under tension is an exciting story. This was on girl's experience. She was my class mate and I know her because she starts class when I finished mine. I told this story here too. Her GZ always run out of tune. Her GZ spend more time at school for tuning than at home for practice. When string come under tension it takes time for them to settle into position for a good grip. It usually takes a week. In the interim the position will run and tuning is required again. It the case of my class mate GZ it will always run. I asked my teacher about it and he told me about string under tension. Feeling sorry for my class mate, I taught her how to tune with a tuner and that solved her problem.
If all this is too complicated, you can bring your GZ to me. I can teach you how to tune with a tuner. No need to buy tuner just download one. By the way I am meeting with KC Leong this Sunday. You are welcome to join us.
sound so complicated. Anyhow, this end month merdeka holiday I will go back ipoh and bring back my GZ first. will look into my andriod apps to lok for a GZ tuner. if can't find then i will buy it from taobao.com which is selling for RMB 39.90.