A DI tank can be the compact choice for a manageable work month. The same tank can also become a resin-replacement problem when source-water TDS or pure-water demand rises. Enter the water and workload you expect to use; the selector shows the published-table estimate, the arithmetic behind it and the reason a DI-only or RO/DI path deserves the next comparison.
The result does not select a product. It narrows the filtration path and identifies the exact measurements and documents that still control the purchase.
DI capacity and workload check
Put your source water and work month on the same page
The result shows the published-table estimate and the exact reason a DI-only or RO/DI path deserves the next check.
- Estimated DI capacity
- Stated monthly demand
- Planning interval
This is a planning estimate, not a replacement date or performance guarantee. Measure output TDS and verify the exact system manual.
Read the estimate before choosing a cart
The capacity figure uses the relationship reproduced by XERO’s published DI tank table for its 0.5- and 1.0-cubic-foot vessels between 50 and 1000 ppm source TDS. Monthly demand is the daily gallons you enter multiplied by the number of workdays. Dividing estimated capacity by that demand produces a planning interval.
That interval is useful for comparing paths, not forecasting an exact replacement date. Resin formulation, channeling, changing source water, flow, storage and the selected equipment can change real service life. Measure source water again when the supply changes, monitor output TDS during use and follow the manual for the exact tank or system.
Why 100 ppm starts a comparison instead of ending the decision
XERO’s current TDS guidance places readings under 100 ppm on the DI side and sends readings of 100 ppm or more toward a multi-stage comparison. This selector treats that split as vendor guidance, not an industry rule or a water-quality guarantee. Workload still matters: a low-TDS source can create frequent resin service when monthly use is high, while a comparison result still requires exact RO/DI output, pressure, consumables and maintenance facts.
If the tool returns DI-only is still plausible, keep DI in the shortlist and verify the expected service pressure against the actual work. If it returns Put RO/DI into the next comparison, price and document both paths instead of assuming that a larger machine automatically wins. A high-flow review means the capacity arithmetic cannot establish whether a pump, membrane or simultaneous-pole setup can deliver the required output.
Carry four checks into the product documents
| Check | What to verify | Why it matters |
|---|---|---|
| Output monitoring | Meter location, target output TDS and the maker’s service threshold | A capacity estimate cannot prove the water arriving at the brush remains within the intended limit. |
| Pressure and flow | Required inlet pressure, pump conditions, rated output and number of poles | A filtration path that looks economical can still miss the actual delivery requirement. |
| Membrane and reject water | RO membrane rating, flushing instructions and any published reject-water requirement | RO/DI adds operating conditions and maintenance that a resin-capacity number does not show. |
| Storage and consumables | Loaded dimensions, drainage, freeze protection, filters, resin and replacement access | The complete system has to fit the vehicle, service routine and available storage. |
Use the complete water-fed pole system guide to connect the filtration result to brush-end delivery, working reach, hose, transport and maintenance. Do not freeze the filtration choice while one of those handoffs remains unknown.
The selector runs in your browser. The measurements are not sent to the website or stored by the tool.