On the home Ro reverse osmosis water purifier cartridge problem

UDF is granular activated carbon, and CTO is block activated carbon, also known as precision activated carbon, filtration accuracy than the UDF is a little higher than the UDF, as to whether or not to use together, there is no relevant requirements, usually in order to protect the RO membrane are the first to do a good bit of pre-treatment on the addition of two pieces of activated carbon, or filtering too many impurities will clog reverse osmosis membranes