How DI Tank Exchange Works
The service is simple by design. You install DI exchange tanks on your site — typically two or more, so one is in service while the other is held as backup. Water flows through the tanks, picking up purity as ions are exchanged out. When resistivity drops below your target specification, you call for an exchange (or we arrive on a pre-set schedule), the exhausted tank is swapped for a freshly regenerated one, and the cycle continues.
| Step 1 | Site evaluation. We review your source water analysis, daily DI water requirement, peak flow rate, and quality specification. From this we recommend tank size, configuration (single-bed cation/anion or mixed-bed), and exchange frequency. |
| Step 2 | Installation. Our technicians deliver and plumb in the tanks. Typical installation is a few hours; existing systems can usually be retrofitted to accept exchange tanks with minimal disruption. |
| Step 3 | In-service operation. Tanks produce DI water to spec. You monitor resistivity (or we provide remote monitoring), and your team operates the rest of the process normally. |
| Step 4 | Exchange. When resistivity approaches your minimum spec, you call us (or we arrive on schedule). Our technicians swap the exhausted tank for a fresh one — no production interruption when sized correctly. |
| Step 5 | Off-site regeneration. Exhausted resin returns to our Houston facility. Resin is regenerated with acid (cation) and caustic (anion), rinsed, tested for capacity and water quality, and rebuilt into a service-ready tank. |
Why Texas Companies Choose DI Tank Exchange
Tank exchange isn’t right for every facility — high-volume continuous users (above roughly 10,000–15,000 gallons per day) often have better economics with a permanent on-site regenerable system or RO+EDI. For everyone else, exchange is the dominant solution. Here’s why:
No Capital Investment
You pay for the water you use, not for equipment you own. The tanks remain Mueller’s property; you pay a service charge that covers tank rental, delivery, regeneration, and quality testing. This shifts a six-figure capex decision into a monthly operating expense — often easier to approve, and easier to scale up or down as demand changes.
No Regeneration Chemicals On Site
Regenerating DI resin requires concentrated sulfuric or hydrochloric acid and sodium hydroxide. Storing and handling those chemicals on your site means safety training, secondary containment, permit considerations, and waste neutralization. Tank exchange moves all of that to our regeneration facility, where it’s the daily routine.
No In-House Expertise Required
Running an on-site DI system well requires understanding when resin is exhausted, how to regenerate it correctly, and how to troubleshoot when water quality drops. With tank exchange, that expertise lives at Mueller. Your team focuses on the process the DI water feeds — not on the DI system itself.
Predictable Cost & Uptime
Service intervals are predictable based on your measured water usage. Backup tanks are standard, so a longer-than-expected resin run never results in production downtime. Monthly costs are forecastable, which makes budgeting straightforward.
Scales With Your Operation
Need more capacity for a new production line? We add a tank. Seasonal peak demand? We adjust the exchange schedule. Closing a facility? You return the tanks. There’s no stranded capital and no equipment to sell off.
DI Exchange Tank Sizes & Configurations
Tanks are sized to match your daily flow, source water TDS, and required purity. We typically deploy one of three configurations:
Cabinet & Small Laboratory Tanks
Smaller-footprint exchange tanks for laboratory and benchtop use, typically producing several hundred to a few thousand gallons between exchanges. Common for clinical labs, research facilities, calibration labs, and dental practices. Often configured as mixed-bed for Type II laboratory-grade water out of the tank.
Standard Industrial Tanks
Mid-size tanks (commonly in the 1–3 cubic foot range) for medium-volume industrial applications — parts washing, plating rinse, optical cleaning, small-volume battery manufacturing, light boiler makeup. Available in single-bed (separate cation and anion) for moderate-purity applications, or mixed-bed for higher purity.
Large-Capacity Industrial Tanks
Larger tanks (typically in the 3–7+ cubic foot range, with larger custom sizes available) for high-volume industrial users. Common applications include semiconductor and microelectronics rinse stations, large plating and finishing operations, EV battery production, and primary deionization in central plant water systems. Often deployed as two-bed (cation + anion) trains with mixed-bed polishing tanks downstream.
Water Quality You Can Expect
Mueller’s mixed-bed exchange tanks are guaranteed to produce up to 18 megohm/cm resistivity at 25°C — the practical maximum for ion exchange. Typical configurations and their water quality:
| Configuration | Typical Resistivity | Common Use |
|---|
| Two-bed (cation + anion) | 50K – 1 MΩ-cm | Industrial rinse, cooling, general working DI |
| Mixed-bed (standalone) | 1 – 18 MΩ-cm | Laboratory, USP pre-treatment, electronics |
| Two-bed + mixed-bed polish | Up to 18 MΩ-cm | Semiconductor, ultrapure, high-purity central plant |
| RO pre-treatment + mixed-bed | Up to 18 MΩ-cm | Highest purity with extended tank life |
Industries & Applications We Serve with Tank Exchange
Tank exchange is technology-neutral — almost any DI water application that doesn’t require enormous continuous flow can be served by exchange tanks. Our customer base spans:
- Industrial manufacturing: metal finishing, plating, anodizing, electropolishing, precision parts washing, cutting fluid makeup.
- Electronics & semiconductor: wafer rinse, PCB assembly, optical coating, lens manufacturing.
- EV battery & energy storage: electrolyte preparation, cell rinse, cooling system makeup.
- Power generation: boiler feedwater polishing, NOx control water, combustion turbine inlet cooling.
- Pharmaceutical & life sciences: USP Purified Water pre-treatment, biotech process water, cleaning validation, lab support.
- Laboratory & research: clinical labs, environmental testing, university research, calibration labs, contract testing facilities.
- Healthcare: hemodialysis pre-treatment, sterilization equipment makeup, clinical lab support.
- Food, beverage & cosmetics: product water polishing, ingredient water for high-purity applications.
- Cooling tower & HVAC: high-purity makeup for closed-loop systems where mineral content must be controlled.
- Window washing & exterior cleaning: spot-free rinse for commercial window and facade cleaning operations.
Texas Service Area
Mueller Water operates from four Texas locations, giving us same-day or next-day exchange capability across the state’s major industrial corridors:
- Houston Headquarters: 1500 Sherwood Forest St, Houston, TX 77043 · (713) 467-3226. Greater Houston, the Energy Corridor, Pasadena, Baytown, Galveston, and the broader Gulf Coast industrial belt.
- San Antonio: 8957 E IH 10, Converse, TX 78109 · (210) 490-4040. San Antonio metro, New Braunfels, Seguin, the Eagle Ford region.
- Austin: 1512 Central Commerce Circle, Pflugerville, TX 78660 · (512) 444-4404. Austin metro, the I-35 tech corridor, Round Rock, Cedar Park, Georgetown.
- Dallas / Fort Worth: 1825 High Prairie Rd #B, Grand Prairie, TX 75050 · (214) 467-0029. DFW metroplex, Arlington, Plano, Frisco, and surrounding North Texas industrial centers.
Toll-free: 1-888-678-6411 · Mon–Fri 7:00 AM – 4:00 PM CT
What’s Included in Mueller’s DI Tank Exchange Program
Custom Resin Selection
Resin selection is matched to your source water and target purity. Standard cation, anion, and mixed-bed virgin resins are stocked; specialty resins (nuclear grade, food grade, low-extractable, specific selectivity) are available for applications that require them. Every lot received from our resin suppliers is inspected against manufacturer specifications before deployment.
Off-Site Regeneration at Mueller’s Houston Facility
All regeneration happens at our Houston regeneration facility — not at your site, not subcontracted to a third party. Regeneration follows documented procedures with acid and caustic dosing rates, rinse volumes, and quality testing. Each regenerated tank is tested for capacity and effluent quality before being approved for redeployment. We also offer standalone resin regeneration services for customers who own their own DI vessels.
Same-Day or Next-Day Exchange (Standard)
Standard exchange response is same-day or next-day across our Texas service area. Critical-process customers can arrange standing service schedules so exchanges happen before exhaustion rather than reactively.
Trained Service Technicians
Mueller technicians handle physical tank exchange — disconnecting exhausted tanks, connecting fresh ones, verifying flow and resistivity at startup, and removing exhausted tanks from your site. Your staff isn’t responsible for any of the exchange labor.
Performance Monitoring
We track each customer’s usage patterns and exchange history. This lets us anticipate exchange timing, flag changes in source water quality (which often shows up as faster resin exhaustion), and recommend system adjustments before they become problems.
Water Quality Guarantee
Mueller’s mixed-bed DI exchange tanks are guaranteed to produce water quality up to 18 megohm/cm resistivity at 25°C, as specified for your application. We document each tank’s effluent quality before deployment.
DI Tank Exchange vs. Permanent On-Site DI System
The right choice depends mostly on water volume and the value of capital flexibility. As a rough decision framework:
| Factor | Tank Exchange Favored | On-Site System Favored |
|---|
| Daily DI water usage | Under ~10,000 GPD | Above ~10,000 GPD |
| Capital availability | Limited or prefer OpEx | CapEx-funded project |
| Chemical handling tolerance | Cannot or prefer not to handle acid/caustic | Already permitted for chemical handling |
| Demand variability | Variable or growing demand | Steady high-volume baseload |
| In-house water expertise | Limited | Dedicated water/utilities team |
| Site footprint | Tight | Room for permanent skid + chem storage |
Many of our largest customers use both: a permanent on-site primary system for baseload, with tank exchange for polishing, backup, peak demand, and remote points of use. We can engineer either path.
Related Mueller DI Services
Tank exchange often fits into a broader water treatment program. Related services we provide:
- Resin regeneration services for customers who own their DI vessels but want off-site regeneration without running their own regeneration facility.
- Mobile rental DI equipment for temporary capacity needs — system outages, construction project water, seasonal peaks, or pilot trials of DI water in a new process.
- Permanent on-site DI system design & installation for high-volume users who outgrow tank exchange economics.
- Pre-treatment design — softening, carbon filtration, reverse osmosis — to extend tank life and reduce exchange frequency.
- Diagnostics & repair on existing DI systems regardless of original manufacturer.
Start DI Tank Exchange Service
Setting up DI tank exchange service is straightforward. We need three things to give you an accurate scope and quote:
- A water analysis of your source water (or your local utility’s most recent water quality report, which we can pull for you).
- Your daily DI water usage estimate — gallons per day, peak flow, and how usage is distributed (continuous, batched, intermittent).
- Your required water quality — resistivity or conductivity specification, or a description of what the DI water is used for so we can recommend an appropriate target.
If you’re not sure on any of these, that’s normal — we’ll help you work through them on a brief site visit or phone call. Most customers go from initial conversation to tanks in service within two to three weeks.
Contact Mueller Water: Houston (713) 467-3226 · San Antonio (210) 490-4040 · Austin (512) 444-4404 · Dallas/Fort Worth (214) 467-0029 · Toll-free 1-888-678-6411
Frequently Asked Questions About DI Tank Exchange
How often do DI exchange tanks need to be swapped?
Exchange frequency depends on three things: tank size, source water TDS, and your daily usage. A 3.6 cubic foot mixed-bed exchange tank treating softened, dechlorinated Texas municipal water might last 4,000–8,000 gallons before resistivity drops below specification. The same tank on harder or higher-TDS feedwater could exhaust in roughly half that volume. After your first few months of service, we’ll have enough data to predict your exchange schedule within a few days.
Do I need to install anything to receive DI tank exchange service?
You need inlet and outlet plumbing connections, a clear floor space for the tanks (we’ll size this during the site visit), and ideally a resistivity monitor on the outlet line so you know when to call for an exchange. Most facilities already have suitable plumbing or need only minor modifications. If you don’t have a resistivity monitor, we can supply and install one.
What if my tanks exhaust faster than expected?
This usually means source water quality has changed — often a municipal water treatment plant has switched supply sources, increased chlorination, or had a temporary upset. We monitor for this pattern across our customer base, and if you notice faster exhaustion we’ll investigate. Backup tanks ensure you don’t run out of DI water during the troubleshooting.
Can I get DI tank exchange service if I’m outside the Houston / Austin / SA / DFW metros?
Often yes. Our four service locations cover most of Texas with reasonable drive times, and we serve customers in smaller cities and rural industrial sites throughout the state. Service economics depend on distance and exchange frequency — call us with your location and we can confirm what’s practical.
What’s the difference between portable DI exchange and PEDI?
They’re the same thing. PEDI stands for Portable Exchange Deionization and is the industry’s older formal term. “DI tank exchange” and “DI exchange service” are the more common everyday names. All refer to the same service: ion exchange tanks delivered and swapped on a service basis, with off-site regeneration.
Can I lease tanks instead of paying per-exchange?
Yes. Most of our customers pay for service on a per-exchange or monthly-service basis. Some prefer a fixed monthly fee that includes a defined number of exchanges. We’ll structure billing the way that works for your accounting and your usage pattern.
What happens to the exhausted resin?
It’s regenerated and reused. Resin regeneration restores the ion exchange capacity by stripping out the captured ions with acid (for cation resin) and caustic (for anion resin). Properly cared-for resin can be regenerated many times before eventual replacement. When resin does reach end of life, Mueller handles disposal in compliance with applicable regulations.
Do I need a softener before DI exchange tanks?
In most cases, yes. Softening removes calcium and magnesium, which would otherwise consume a disproportionate amount of your cation resin capacity. Softening typically extends DI tank life by 50% or more and is one of the simplest ways to reduce service costs. We can include a softener in the system design or work with one you already have.