Spectrum filtration specialist sealed 20inch mixed bead DI redin cartridges for water purification in RO process etc. I have contacted spectrum to see if theres a shelf life expectancy and the response was there is not. Each cartridge is fully sealed and boxed and these things cost a whopping £190ish each Had these for a while from a storage container i purchased, I intended to use them but shut my aquarium down so I'm going to sell them at a reduced price Please see my other items. Any further info head over to spectrums site
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