comments:
febu_max posted on r/laundry2w
If you can get it, that's your unlock provided the listing says "sodium tripolyphosophate" and not "sodium triphosphate." You need the poly! It's about 2-3x more potent than sodium citrate. My water is 25-50ppm (sorry!), but this seems good and I've bought other chemicals from them for bench testing: https://www.amazon.com/Tripolyphosphate-Eco-Friendly-Packaging-Powerful-Cleaning/dp/B091579GHX