RO/DI question

[hillegom]

I agree with Myka about efficiency
Here is what one ebay seller said about coconut carbon

Carbon Cartridges are extruded carbon block with coconut carbon. Coconut carbon is a premium carbon that gives water a great taste, and some contend a "sweeter taste."

I would think something burned to carbon is the same for all materials. What do you have left? Just carbon IMHO