DI Resin is necessary to reduce Total Dissolved Solids (TDS) to zero and is usually use as the last stage filtration of an RO/DI unit. It is not necessary to use the expensive proprietary DI cartridges that other RO manufacturers sell. Simply buy a refillable DI cartridge if you don’t have one already and fill with DI resin. You’ll save money and get the same results.
To get maximum life from your DI resin please takes the following steps
Ensure optimal operation of your RO membrane. The higher your membranes rejection rate the fewer TDS your product water will contain resulting in longer lasting resin. The best way to keep the membrane rejection rate up is to monitor and change your prefilters appropriately as well as maintain at least 50psi going into the membrane.
Ensure the resin is packed in the cartridge securely. The resin should be packed very tightly. When squeezed, there should be almost no flex to the cartridge.
The initial couple minutes of water from your RO membrane will always be high, this is commonly referred to as TDS creep. Diverting the first few minutes of water down the drain can often greatly reduce DI resin consumption.
Maintain low levels of carbon dioxide in your water supply. Excess carbon dioxide will deplete DI resin quickly. If you are depleting resin quickly and have already :addressed the two options above, excess carbon dioxide is the likely culprit. You have two choices:
Collect the water coming from your RO system in a large container, add a powerhead or air stone and allow the CO2 to gas off. Then pump the water though your DI resin.
Skip all that mess and just buy resin in bulk.
** The life span of the DI resin will very much depends on the TDS reading of the tape water source.