ZeroWater uses a mixed bed ion exchange resin (anion and cation) to attract and hold dissolved ionized solids. Mixed bed resin is very effective and will remove nearly 100% of dissolved solid content which will includes all heavy metals.

The downside of mixed bed resins is that they are not selective and water with high dissolved content (TDS) will deplete the resin at very fast rate. Price per gallon is comparable to bottled water with moderate to high TDS. They are simple and very effective as long as the filter is replaced as needed.