I ran downstairs over the long weekend to mix up some salt water for a water change and my RO unit has decided to almost stop working. It still drips some water, but at a rate just high enough to keep up with evap. Pretty much happened overnight. It has been slowing down, but has always keeped up with my schedule. I think my filters are shot so I need some replacements. What do i need to look for on the unit to find out what kind of replacement filters I need? It is marked on the unit? I forgot to check before I came to work and was wondering if I could get away with ordering some today so I can have them by the end of the week, without knowing the model of unit I have. any which filters should I replace. any ideas?