Hydrous manganese oxide (HMO), a high surface area floc, has a unique adsorptive affinity for capturing radium 226 and 228 ions in water.  Freshly precipitated HMO is formed by combining Carus permanganates with Carus manganese sulfate, producing a 1% to 10% slurry.  When injected into a groundwater source prior to filtration, HMO quickly adsorbs the radium ions and they are removed on the filter.