Tidal Wave Mixer: Active Mixing for Municipal Water Storage Tanks
If you are chasing a chlorine residual that will not hold, seeing your top-of-tank samples come back different from your bottom-of-tank samples, or heading into another summer of nitrification in a chloraminated system, the underlying cause is usually the same: your tank isn’t one body of water. It is layers.
The Tidal Wave Mixer is a municipal water tank mixer that eliminates thermal and residual stratification in potable water storage tanks and standpipes. It weighs 32 pounds, fits through a standard access hatch, installs in under 30 minutes without draining or taking the tank offline, and your staff can service it.
That combination — real mixing energy in a package one person can carry up a ladder — is what separates it from systems that require cranes, tank entry, or a factory return for service.
How the Tidal Wave Mixer Works
Water in a storage tank does not mix itself. Inlet and outlet momentum in a typical fill-and-draw tank is far too low to turn over the full water column, and the physics work against you: warmer water is less dense and rises, colder water settles, and a thermocline forms between them. Once that boundary sets up, the two layers stop exchanging.
How completely they stop exchanging is worth seeing measured. In an independently instrumented 102-foot steel standpipe, temperature loggers placed every ten feet from floor to surface showed a 15-degree spread — and the only depth showing any movement at all under normal operation was a narrow band roughly 20 feet above the floor. Water entering through the floor inlet rose about that far, mixed slightly, and was drawn back out. The upper 80 feet of the tank was effectively stagnant.
The consequences show up in your sample results before they show up anywhere else. Disinfectant residual decays fastest in the warm, stagnant upper layer — exactly the water that leaves the tank first on a heavy draw. Water age climbs in the zones that never move. In chloraminated systems, that warm stagnant layer is where nitrification starts.
The Tidal Wave Mixer breaks that structure by driving active, high-energy circulation through the full water column, pulling colder water from the tank floor and driving it upward to continuously disrupt the thermocline and force the tank to behave as a single uniform body of water.
The result is consistent temperature from top to bottom, uniform disinfectant residual throughout, and dramatically reduced water age in what used to be the dead zones.
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Rigorously Tested and NSF-61 Certified
Our water tank mixer for potable drinking water has been tested and meets or exceeds the stringent standards for Water Quality Association, NSF/ANSI/CAN 61, and NSF/ANSI/CAN 372 approvals. This powerful active water mixer is designed for small or large potable water storage tanks (250k—10+ million gallons). It features a robust High-Density Polyethylene (HDPE) frame that ensures superior chemical resistance and offers advanced safety features for easy installation.
Download and view our NSF/ANSI/CAN certification here.
The Combined System — How It Performs Best
The Tidal Wave Mixer solves stratification. On its own, that is often the whole answer. But two of the problems it gets called in for — TTHM exceedances and chloramine residual loss — are solved more completely when the mixer is paired with the system built for that specific problem. For TTHM compliance: Trihalomethanes are not uniformly distributed in a stratified tank, and they cannot leave the water until they reach the surface. The Hurricane Blower actively ventilates the tank headspace, pulling volatile compounds out of the airspace so more can off-gas from the water. The Mixer continuously presents fresh water to that ventilated surface. Operating together, utilities have documented 20–25% reductions in chloroform concentrations — the most common TTHM driver in drinking water systems. For chloramine residual: Dosing chemical into a stratified tank puts your chemical where the water is not moving. The Chloramine Boosting System doses precisely; the Mixer distributes that dose through the entire volume instead of leaving a treated pocket and an untreated remainder. Combined, you get a consistent total chlorine residual across the tank rather than a good sample point and a bad one. The Mixer is the multiplier. Every chemical or ventilation strategy applied to a storage tank works better when the tank is actually mixed.
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Most utilities do not have a stratification problem on their compliance report. They have a residual problem, a water age problem, a nitrification problem, or a TTHM problem. Stratification underlies all four.
It goes unnoticed because almost nobody measures it. A single sample tap — usually near the outlet — reports one number for a tank that may have a 15-degree temperature spread from floor to roof. The sample is accurate. It is just not representative.
Here is what it looks like when someone does measure it. In a 9-million-gallon concrete reservoir, free chlorine grab samples taken before the mixer was started measured 1.30 PPM near the floor and 0.65 PPM at the surface — a 50% difference in disinfectant residual inside a single tank. Temperature sensors in the same tank showed 6.5°F of stratification.
What it costs when it goes unaddressed:
- Chemical you are paying for and not getting credit for. Dosing to hold a residual at the sample point means overdosing the tank as a whole.
- Water age in the layers that never move, which drives DBP formation and residual decay.
- Nitrification risk in chloraminated systems, which begins in warm stagnant zones and is far more expensive to break than to prevent.
- Deep cycling and the pumping cost that comes with it, when utilities drop and refill tanks to force volume exchange because they have no other way to move the water.
- Freeze exposure in cold-climate tanks, where the surface ices while warmer water sits unused below it.
None of these appear on a line item called “stratification.” They appear as chemical cost, pumping cost, a compliance notice, and operator hours.
The Cost and Labor Reality
Most active mixing systems carry costs beyond the equipment price that do not surface until you are scheduling the work.
Conventional systems commonly require some combination of: taking the tank offline, draining it, confined-space entry, crane or lift equipment, a multi-person crew, and a factory return when the unit needs service. For a utility running lean on staff, that is often the real barrier — not the purchase order.
Walnut Valley Water District described the problem directly. Before switching to the Tidal Wave Mixer, their operators were pulling 60-plus-pound mixers off reservoirs over 30 feet tall for repair and replacement. Their Production and Storage Supervisor called it a logistical nightmare, and noted that operators could not tell by visual inspection whether the units were even still running.
The Tidal Wave Mixer was designed around removing those costs:
- One person, under 30 minutes. At 32 lbs, it fits through a standard access hatch without modification and does not need a crane.
- No draining. No offline time. The tank stays in service through installation.
- Field serviceable by your own staff. It is the only water tank mixer on the market that municipal staff can service. You never send it to the factory.
- Lower operating cost downstream. Utilities have reduced hypochlorite dosing and eliminated deep-cycling pump runs after installation.
What It Will and Won't Do
We want operators and engineers to have accurate expectations before they pick up the phone.
Where it performs: The Tidal Wave Mixer eliminates thermal and residual stratification in potable storage tanks and standpipes from 250,000 gallons to over 10 million gallons. In a 9-million-gallon reservoir, sensors at three depths converged within 4.5 hours of startup, and 6.5°F of stratification was fully eliminated within 24 hours — with one mixer. In a 102-foot standpipe with a 15-degree spread, the full water column reached a uniform 77°F within 6 to 8 hours and held uniform through the following 48 hours of normal operation, including fill cycles. If your problem is a temperature or residual gradient inside the tank, this is squarely the right tool.
Where it does more than operators expect: In chloraminated systems experiencing nitrification, mixing alone has raised total chlorine residual with no additional chemical. At Walnut Valley Water District, nitrite in two reservoirs fell from 0.022 to 0.004 PPM and from 0.014 to 0.003 PPM within 24 hours of startup, with total chlorine rising from roughly 1.5 to over 2.5 PPM in both. No sodium hypochlorite was dosed. The residual wasn’t being created—it was being kept from disappearing.
In free chlorine systems, mixing has let utilities hold a higher residual on less chemical. A Southern California city that had been deep-cycling reservoirs — dropping and refilling tanks ten to twelve feet to force volume exchange — eliminated the practice entirely after installation and moved from a 0.05–0.30 PPM residual range to a sustained 0.50–0.75 PPM while dosing less hypochlorite.
Where it helps but is not the whole answer: Mixing reduces water age and improves residual distribution, and it has been shown to help reduce TTHM. But mixing alone does not remove trihalomethanes — it brings them to the surface where they can leave. If TTHM compliance is your primary driver, evaluate the Mixer alongside the Hurricane Blower rather than on its own.
Where it will not solve the problem: Stratification is a tank problem. If your residual loss, DBP formation, or nitrification is originating in the distribution system downstream of the tank, or in your source water and treatment upstream of it, a mixer will not fix it. We would rather tell you that on the phone than sell you a unit that does not move your numbers.
Site requirements: Power to the mixer control panel. A standard access hatch. The mixer installs below the hatch and does not require draining the tank or taking it offline.
Technical Specifications
| Specification | Detail |
|---|---|
| Weight | 32 lbs |
| Tank Capacity Range | 250,000 to 10,000,000+ gallons |
| Horsepower Options | 0.5 HP - 3 HP |
| Construction | High-Density Polyethylene (HDPE) frame |
| Certifications | NSF/ANSI/CAN 61, NSF/ANSI/CAN 372, Water Quality Association |
| Tank Types | Steel and concrete; reservoirs and standpipes |
| Mounting | Suspended below standard access hatch |
| Typical Installation Time | Under 30 minutes, one person |
| Tank Downtime Required | None - no draining, no offline time |
| SCADA Compatible | Yes |
| Field Serviceable | Yes - by municipal staff, no factory return |
Frequently Asked Questions
Is the water tank mixer easy to Install?
Yes. Most customers can drop our water tank mixer into a tank in less than 30 minutes. By far, it is the easiest to install of all water tank mixing systems.
How much does the water tank mixer weigh?
The Tidal Wave Mixer weighs 32 lbs. It fits inside a standard-size access hole without modification.
Can you guarantee uniform temperature in a potable water tank?
We have measured it repeatedly. In a 9-million-gallon reservoir, we eliminated 6.5°F of thermal stratification within 24 hours with a single mixer. In an independently instrumented 102-foot standpipe with a 15-degree spread from floor to surface, the full water column reached a uniform temperature within 6 to 8 hours and held uniform through 48 hours of normal operation. Results depend on tank geometry and operating conditions, and we will review yours before recommending a configuration.
Do I need to drain the tank to install the water tank mixer?
No. You do not need to drain the tank to install the water tank mixer
Do I need to take the tank offline to install?
No. You do not need to take the water tank offline to install the water tank mixing system.
Is the water tank mixer NSF/ANSI 61 certified?
Yes. The Tidal Wave Mixer Is NSF/ANSI 61 certified.
Can your water tank mixer withstand chlorine or chloramines?
Yes, You can add chlorine or chloramines to the water you mix.
Will a mixer help with nitrification in a chloraminated system?
Yes, and in some systems dramatically. Nitrification begins in warm, stagnant zones where chloramine residual has decayed. Eliminating stratification removes those zones. At Walnut Valley Water District, nitrite levels in two reservoirs fell from 0.022 to 0.004 PPM and from 0.014 to 0.003 PPM within 24 hours of mixer startup, with total chlorine residual rising from roughly 1.5 to over 2.5 PPM in both — with no additional chemical dosed.
Can mixing raise my chlorine residual without adding more chemical?
In systems where residual is being consumed by nitrification or lost in stagnant zones, yes. Mixing does not create disinfectant, but it stops the conditions that destroy it and distributes what you are already dosing across the full volume. Multiple utilities have raised sustained residual while reducing hypochlorite use.
Are your water tank mixers used for freeze protection?
Yes. Our water tank mixers can be used for freeze protection.
Do water tank mixers help remove TTHM in drinking water?
Mixing helps by eliminating the stratification that concentrates TTHMs in specific zones and by continuously bringing water to the tank surface where volatiles can off-gas. On its own, mixing reduces TTHM but does not remove it. Paired with the Hurricane Blower, utilities have documented 20–25% reductions in chloroform concentrations. If TTHM compliance is your driver, we would want to look at both systems together.
How much horsepower does your water tank mixer use?
We have solutions ranging from .5 HP to 3 HP
Could a local technician maintain your water tank mixer, or should it be returned to the factory for service?
The Tidal Wave mixer is the only water tank mixer on the market that municipal staff can service. You don't need to send it to the factory for service... ever.
Can your water tank mixer be connected to SCADA?
Yes. The Tidal Wave Mixer can be connected to SCADA.
Can a mixer replace deep cycling?
For many systems, yes. Deep cycling — dropping and refilling tanks to force volume exchange — is a workaround for a tank that will not mix itself. A Southern California city eliminated the practice entirely after installing the Tidal Wave Mixer, reduced its hypochlorite dosing, and cut the pumping energy required for deep cycling.
What causes thermal stratification in a water storage tank?
Warmer water is less dense than colder water, so it rises and stays at the top of the tank. Inlet and outlet momentum in a typical fill-and-draw tank is not strong enough to overcome that difference, so a thermocline forms and the layers stop exchanging. The upper layer then loses disinfectant residual faster and ages faster than the water below it.
How do I know if my tank is stratified?
The direct test on a municipal water tank mixer installation is a temperature or residual profile taken at multiple depths rather than a single sample at the outlet. In an instrumented 102-foot standpipe, loggers spaced ten feet apart revealed a 15-degree spread and showed that only a narrow band about 20 feet above the floor was moving at all. Indirect signs include a residual that will not hold at the far end of the system, seasonal TTHM spikes, nitrification episodes in warm months, and a habit of deep cycling to keep water quality acceptable.
Case Study — 102-Foot Steel Standpipe, Connecticut
This study was not conducted by Big Wave Water. CorrTech, a corrosion engineering firm, ran it independently.
The subject tank was a welded steel standpipe, 102 feet tall and 35 feet in diameter, with a single combined inlet/outlet in the tank floor — a configuration that gives incoming water almost no help in reaching the upper volume.
Method. Eight submerged temperature data loggers were suspended through the roof hatch at 10-foot intervals from the floor to just below the water surface, recording every 10 minutes. The tank ran normally for 48 hours to establish a baseline. The Tidal Wave Mixer was then installed and energized, and the loggers recorded for another 48 hours.
Baseline. The tank held a 15-degree temperature spread — 68°F at the floor to 83°F near the surface. The only depth showing any mixing under normal operation was a narrow band 20 to 22 feet above the floor. Fresh water entering at the floor rose to roughly that depth, fluctuated slightly, and was drawn back out as needed. The water above it was not moving and was not reaching customers.
After the mixer was energized. The entire water column reached a uniform temperature of approximately 77°F within 6 to 8 hours, and remained uniform for the full 48 hours the mixer operated. Fill events no longer created layers — incoming cold water was completely blended with the standing volume before leaving the tank.
CorrTech’s conclusion. A fully mixed tank, as indicated by uniform temperature, ensures uniform chlorine residual throughout, and the distribution system receives consistent water quality even during heavy draw.
Not Sure If a Mixer Is What Your Tank Needs?
Most of the conversations we have start the same way — an operator has a residual that will not hold, a compliance letter, or a tank that behaves differently in July than it does in January, and needs to know whether a municipal water tank mixer is a realistic fix that does not require a capital project.
That is exactly what we are here to help you work through. Tell us what you are dealing with — tank size, what your sample data is showing, what you have already tried — and we will give you a straight answer, including whether we think this is the right fit.
More Evidence From the Field
Nitrification and Residual Recovery — Walnut Valley Water District, CA. Three reservoirs, 1 MG to 2.4 MG. Nitrite reduced by up to 82% and total chlorine residual raised from roughly 1.5 to over 2.5 PPM within 24 hours, by mixing alone with no additional chemical. Download the study (PDF)
Eliminating Deep Cycling — 5 MG Reservoir, Southern California. Uniform residual reached within 90 minutes of startup. Sustained free chlorine moved from 0.05–0.30 PPM to 0.50–0.75 PPM while reducing hypochlorite dosing, and deep cycling was eliminated along with its pumping cost. Download the study (PDF)
Thermal and Residual Uniformity — 9 MG Concrete Reservoir. 6.5°F of stratification and a 0.65 PPM residual gradient were eliminated within 24 hours with a single mixer. Post-mixing samples measured 1.35 PPM at the surface and 1.37 PPM at the floor. Download the study (PDF)
Our Other Helpful Products:
Struggling to Maintain Chloramine Residual?
Our Chloramine Booster System (CBS) is flexible, precise, and dependably built to maintain consistent chloramine residual in drinking water reservoirs, standpipes, and distribution systems. Gone are the days of hand-carrying chemicals up the ladder! By combining the Tidal Wave water reservoir mixer with the CBS, you obtain a consistent chloramine residual in ways you never thought possible. Learn more…
Reduce Trihalomethanes in Drinking Water
It takes a unique approach to remove trihalomethanes in drinking water. Big Wave Water offers several solutions to this real problem. By combining their active water reservoir mixer with the Hurricane Blower, the actively and thoroughly mixed reservoir water increases the rate at which it can remove trihalomethanes from the drinking water.
This unique blower also drastically reduces corrosion within water storage tanks by eliminating humidity from the tank’s headspace. Learn more…
Hurricane Blower
