I recently bought a house that gets its water supply from a cistern. The roof of my shop and house is piped in to my cistern. So when it rains, thats how I supply water to my house. I have 2 In line filters with one being a carbon 5 micron filter and the second a pleated 20 micron filter that filters the water before it comes to the house. My question is, is using a 20 Mic filter ok to use following a 5 micron carbon filter or do I need to use a 5 micron pleated filter as well? This is a 2000 gallon cistern and I treat it once a week with 1- 2 gallons of bleach, depending on the amount of rainfall I get. Any helpful ideas for a cistern with anything will be helpful. Ive been using the Watts Maxetw--FF20 carbon filter and the watts FM-BB-20-20 pleated filter. These are pretty expensive! Is there another filter out there that cheaper but holds up just as good?