Other technologies include thermal mixing valve, pressure-assisted toilet, recirculation pump, solar water heater, hybrid heat pump water heater, and tank-style electric heater. Filtration media include activated carbon, KDF, ceramic, resin beads, sand filters, and zeolite. Systems for well water may include iron filter, manganese remover, acid neutralizer, UV disinfection, and bacter... https://homewatertech.com/best-condensing-tankless-water-heaters-guide/