Product review (1 stars): Clogs Up, Not the same crystals as original
I have a water softner so I only change the filter once a year. I run the unit in the bedroom only at night.  I read all the mixed reviews. Most are not good.  Bought the refill anyway. Filling the cartridge is not the issue. The problem is that these refill crystals are not the same as the original.  THey're much finer and clog up, the water can't pass thru and your unit shuts down thinking it's low on water even though the reservoir is more than half full. Several oter folks have the experienced same problem.  Makes no sense to me why the manufacturer uses one type of medium in the original unit and replacement cartridges,  and this finer grain type in the refill pack.  Will not buy these again.  I now don't use any filter at all.  Having a water softner seems to be all that you need -- and buying 40 lbs of salt once a year is even more economical not to mention all the other benifts of having soft water.