What should the bed expansion be when backwashing ion exchange units?

When backwashing ion exchange units, the bed expansion should ideally be in the range of 50-75%. This expansion range is crucial as it provides sufficient turbulence to dislodge trapped particulates and regenerate the resin beads effectively without causing them to become damaged or lose their effectiveness.

Expanding the bed within this range ensures that the resin is adequately cleaned, preventing channeling and allowing for even water flow during subsequent service cycles. This not only maintains the efficiency of the ion exchange process but also prolongs the lifespan of the resin.

While a smaller bed expansion (0-25%) might not provide enough agitation to effectively remove all debris and particles, and a very high expansion (75-100%) could lead to excessive movement that might damage the resin beads or lead to loss of material, the 50-75% recommendation strikes a balanced approach for optimal backflushing results.