I have no problems using the KCKT with HEBE. A shower filter doesn't make the water soft, it just filters out certain chemicals and minerals depending on what filter you get. This is the shower filter we have and I think the refills are about $10, if I recall correctly. It mainly filters out chlorine but I can tell a difference in my hair (and skin). I'd love to get one that filters out some minerals but for now, I just poo once every week or two and I can tell a big difference even though the products I use supposedly don't build up. I actually think even conditioner builds up a teensy tiny bit. The shampoo I currently use has cocamidopropyl betaine but I'd like to find one a with a gentler cleanser that will also remove hard water buildup.
May I ask what you use the AOMM for? Is it for curl enhancement or more of a gel for hold? I can't recall if I every tried it or not. I'll have to check out the ingredients.