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Which filter

leaking Member Posts: 46
I just had two AO smith 540 199,000 btu tankless installed in an apartment building. There is a anti scale filter AO sells for about 500$ each, I need two. Is there anything cheaper ? AO sells the smaller filter I can get it for 125$. I think I can use 4 of them but I am looking for other ideas to do this right. 


  • leaking
    leaking Member Posts: 46
    I forgot to say it’s Chicago water, 7.6-8.6 hardness 
  • hot_rod
    hot_rod Member Posts: 22,157
    At that cost a water softener may make more sense? There are some non salt technologies out also, if the brine backwashing is an issue in your area.
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream
  • Larry Weingarten
    Larry Weingarten Member Posts: 3,304
    Hi, Another reason to go with a non-salt softener approach is that salt makes the water more conductive, eating up the anodes in the tanks. I've seen them completely used up in six months with salt softened water. You should leave 3-6 grains of hardness in the water to protect any copper piping as well.

    Yours, Larry
  • Karl Reynolds
    Karl Reynolds Member Posts: 63
    Look at the 3M AP430SS. Relatively inexpensive and easy cartridge changeouts.