There are different types of coolant which should not be mixed. You can no longer rely on it either being blue or pink. So it may be best to get some official Honda 50/50 coolant from someone like Cox motor spares.
I may be overthinking this but are you sure it needs topping up? The recommended min and max level line is not always obvious and the correct level may be halfway down the bottle. Also the level should not drop much in service. If you need to top it up regularly its best to locate and rectify the cause.
That said ,if you are overfilling the bottle/system it may find its own level, and discharge any excess coolant each time through an overflow.
