Dedicated tankless water-heater scale prevention
ZoneGuard Tankless Series
0.8–6.1 US GPM
3/4-inch male NPT
$399.00 USD
$30 U.S. shipping per order
View Tankless →
Stanley Fisher engineering · The ZoneGuard family
Hard water is rebuilding
your plumbing.
Quietly. Daily. Mechanically.
The ZoneGuard family uses a permanent catalytic core to address calcium scale formation — without salt, filter media, electricity, or maintenance.
Salt-free scale prevention for dedicated tankless heaters and whole-home applications. Understand water scale prevention.
Made in England · Manufactured to order · Up to 3 weeks to dispatch
- 3 modelsDefined applications
- Permanentcatalytic core
- 0consumables
- 0power required
One technology. Three applications.
Choose the right ZoneGuard.
Dedicated tankless protection. Whole-home coverage. Higher-demand homes. Each model has a defined application and operating envelope.
Whole-home scale protection
ZoneGuard Plus Series
Up to 12 US GPM
1-inch NPT
$849.00 USD
Free U.S. shipping
View Plus →
Higher-demand whole-home scale protection
ZoneGuard Pro Series
Up to 20 US GPM
1-inch NPT
$1,199.00 USD
Free U.S. shipping
View Pro →Choose by application and actual peak flow, not fixture count alone. Published capacities are not guarantees of simultaneous fixture performance.
10-year limited warranty for Plus and Pro
See the applicable model brochure and warranty terms.
No salt. No media. No power.
Zero consumables. No scheduled maintenance.
ZoneGuard — general brand and technology film (V6)
ZoneGuard · The film
A closer look at the engineering.
A visual introduction to ZoneGuard and its permanent catalytic core. Explore the general technology, then choose the model for your application.
Research & Evidence →What you don't see
The damage isn't on the surface.
It's behind the wall, inside the heater, on every fitting downstream.
The problem, in plain terms
Hard water carries calcium and magnesium. Under the right conditions, scale can form.
Heating and changes in water chemistry can cause dissolved minerals to precipitate and form scale on surfaces in water heaters, appliances and plumbing. The amount of buildup depends on water conditions and use.
Established scale can require cleaning or descaling using methods approved by the equipment manufacturer. Where scale-forming conditions persist, deposits can continue to accumulate.
Managing scale is an ongoing part of protecting equipment and maintaining performance.
A different position
Scale is mechanical.
The solution should be too.
Most products on the market treat scale with chemistry — by adding salt, swapping ions, or layering consumable media. ZoneGuard takes a different position. If the problem is mechanical, the answer should be too.
Explore the research behind catalytic scale prevention and the defined application of each ZoneGuard model.
How it works
A mechanical process, addressed mechanically.
Inside the unit, water flows over a permanent catalytic core. Contact with the core encourages dissolved hardness minerals to form microcrystals carried with the water, rather than bonding as scale to surfaces. No salt or replaceable filter media is added.
Read the scale-prevention research →
-
01
Flow
Water enters the housing at standard line pressure. No power is required. Follow the model instructions and review incoming water conditions with a qualified installer.
-
02
Nucleate
The catalytic surface supports nucleation: dissolved hardness minerals form microcrystals carried in the water.
-
03
Pass
The water carries these microcrystals downstream. ZoneGuard addresses scale formation without removing calcium or magnesium; results depend on water conditions and installation.
Where it goes to work
Protection matched to the application.
Tankless serves a dedicated tankless water heater. Plus and Pro serve whole-home distribution, sized to actual demand. Installation position and connections are model-specific.
Kitchen & dishwashing
Glassware, cookware, faucet aerators, dishwasher heating elements.
Water heating
Dedicated tankless protection with Tankless; whole-home applications with Plus and Pro.
Showers & fixtures
Glass enclosures, shower heads, cartridges, valves, seals.
Proof & observed performance
Installed, in service, observed.
A representative cross-section of residential and light commercial deployments.
We were dealing with scale buildup across our commercial machines, leading to inefficiencies and frequent maintenance. After installing ZoneGuard across multiple locations, we’ve seen a clear reduction in scaling, with equipment running more smoothly and requiring less attention.”
Uncle Osaka
multi-location restaurant group
Field observations vary based on water composition, system design, and installation conditions. Customer observations are not guarantees of performance. ZoneGuard does not remove calcium or magnesium from drinking water.
Compare the categories
Honest accounting. No marketing.
A short look at what each approach is actually doing — and what it costs you over time.
Scroll horizontally to compare all columns →
| Approach | What it does | The compromise |
|---|---|---|
| Salt softener | Ion exchange — strips calcium, releases sodium. | Salt purchases. Drain line. Wastewater. Sodium load. Footprint. |
| TAC media | Polymer beads that seed nucleation. | Media degrades. Replacements scheduled. Performance fades over time. |
| Electronic descaler | Wraps a magnetic or radio-frequency field around the pipe. | Power-dependent. Effects difficult to verify in independent testing. |
| ZoneGuard family | Permanent catalytic core. Mechanical conversion at line pressure. | No consumables. No power. No drain. One installation. |
Total cost over ten years
Honest math, ten years out.
Historical whole-home category estimates are shown for context, not as quotes. ZoneGuard rows show equipment cost only; installation, shipping and import charges are additional where applicable.
ZoneGuard prices come from the current catalog; other rows retain historical estimates. Different applications are not like-for-like performance comparisons. Scroll horizontally to compare all columns →
| Approach | Equipment + consumables + service | 10-year estimate |
|---|---|---|
| Salt softener | ~$1,200 unit · ~$1,500 salt over 10 yr · ~$400 service | ~$3,100 |
| TAC media | ~$900 unit · ~$600 media replacements · ~$300 service | ~$1,800 |
| ZoneGuard Tankless Series | $399.00 USD equipment · no consumables · installation and import charges excluded | $399.00 USD equipment baseline |
| ZoneGuard Plus Series | $849.00 USD equipment · no consumables · installation and import charges excluded | $849.00 USD equipment baseline |
| ZoneGuard Pro Series | $1,199.00 USD equipment · no consumables · installation and import charges excluded | $1,199.00 USD equipment baseline |
Compare all three models
Compare application, flow and connection size. Tankless is a dedicated-heater model, not whole-home coverage.
Tankless · Plus · Pro
One principle. The right application.
Choose Tankless for dedicated tankless water-heater scale prevention within 0.8–6.1 US GPM, with 3/4-inch male NPT connections. Choose Plus for whole-home demand up to 12 US GPM, or Pro for higher demand up to 20 US GPM; both use 1-inch NPT connections.
Manufactured to order in England. Please allow up to 3 weeks for dispatch. Transit time begins after dispatch and varies by destination and carrier.
Shipping, import charges and returns →Installation
Installation starts with the right model.
Use a qualified installer and the instructions for your model. Typical installation time: approximately 30–60 minutes, depending on site conditions and existing plumbing.
-
1
Locate
Tankless: identify the dedicated tankless heater supply. Plus and Pro: review the incoming whole-home supply and actual peak demand. Follow the applicable model instructions.
-
2
Install
Tankless uses 3/4-inch male NPT connections. Plus and Pro use 1-inch NPT connections. The installer selects suitable adapters, confirms pressure and temperature limits, and tests for leaks.
-
3
Operate
No electrical power or salt regeneration is required. Continue the water-heater manufacturer’s maintenance and water-quality requirements.
Questions, answered
Before you order.
Is ZoneGuard a water softener?
No. A traditional softener strips calcium and magnesium from your water using salt-based ion exchange. ZoneGuard is a catalytic crystallizer — it does not remove minerals or add sodium. The water composition is unchanged; what changes is how the calcium behaves on contact with surfaces.
Does it remove minerals from drinking water?
No. Calcium and magnesium remain in the water. If your goal is demineralized water, you would want a reverse osmosis system in addition to ZoneGuard.
Does it require maintenance, replacement media, or power?
No. There is no media to replace, no salt to add, no drain line, and no electrical connection. The catalytic core is permanent and not consumed during operation.
How is this different from a magnetic or electronic descaler?
Electronic descalers attempt to influence scale formation through an external field around the pipe. ZoneGuard uses a physical catalytic core that water flows directly across. There is no external power source and no field that has to "reach" the water.
Will I notice a difference in the shower or on fixtures?
Many users report fewer mineral deposits on glass and fixtures over time and easier routine cleaning. Skin and hair feel are not chemically altered, since the water composition itself is not changed.
Can I install it myself, or do I need a plumber?
Use a qualified installer and the applicable instructions. Tankless uses 3/4-inch male NPT at the dedicated heater supply; Plus and Pro use 1-inch NPT for whole-home applications. Typical installation time: approximately 30–60 minutes, depending on site conditions and existing plumbing.
When will my ZoneGuard be dispatched?
Made to order in England. Please allow up to 3 weeks for dispatch. Transit time begins after dispatch and varies by destination and carrier. U.S. shipping is $30 once per order containing Tankless; Plus and Pro ship free when ordered without Tankless. Import duties, tariffs and brokerage charges may be payable by the recipient, subject to applicable law. Online checkout supports US shipping destinations. Outside the US, email support@stanleyfisher.com to ask about availability and shipping arrangements. Carrier transit and customs clearance are additional and variable; a guaranteed delivery date is not offered. See Shipping & Returns.
For professionals
A direct line for installers.
An application-only network for licensed plumbing and water-treatment contractors.
Product guidance and direct factory support — for the installers who specify engineered systems.
One decision. Made once.
Continuous process.
Permanent solution.
A permanent catalytic core. A defined application for every model.
Tankless. Plus. Pro. Choose the application and verified operating range that fit your system.