I use 1 micron sediment and carbon filters from them. I look at the flow ratings for the filters and get the ones that provide the filtration I want with the best flow rate. A 5 micron filter is like putting cheesecloth over the end of the hose, you'll get a higher gpm (maybe) but be letting a considerably more crud through. I've been using this filter system since we got the rig in 2009. Must be doing something right because my water heater anode is still the original and my tap water tastes like...water. The incoming CG water pressure where we stay is almost 60 psi. After my two filters, I'm sending a bit over 40 psi into the rig. Doesn't sound like a lot, but it's quite adequate. The trade off for using a lower micron filter might be having to change it more often, but that has not been a problem. I have a pressure gauge before and after the filters, along with a water meter going into the rig. With them, I can look for pressure drop and flow rates.