Coolant C4 Cactus Diesel

Hi, I have a question. I drive a C4 Cactus Diesel, and I noticed on the weekend with the obligatory check (oil, wiping water etc.) that my cooling water is already a clear piece under min. Was a good 2 – 3 years ago already under it, then I was simply given a little sip of water in the workshop. But now I want to fill it up a little properly. As far as I have searched correctly, for the cars G33 and G34 is pre-arranged. G34 is in the tank, I guess, is G34 in it. Can I then just tip G34 over? G34 is getting on the internet in proportion but very rare. There are also many universal ones…. Are they going or would G34 be the better choice here? About experience or advice I would be very grateful, or the chance to get G34 on the tank is certainly very low, isn’t it?