NOTE: As of January 1st 2013, development on Fractional brining has ended and the new Differential Brining algorithms have been replaced it.
Original article reprinted below for archival purposes only.
I was speaking with one of my dealers this week, and he commented to me that one of his new employees didn’t “buy into” fractional brining. Once I’d finished laughing hysterically, we discussed the disinformation out there from vendors of generic systems who have no innovative capabilities. I also realized that some people just don’t know any better…
“Fractional Brining” is the term that describes a truly unique way to operate and regenerate ion-exchange systems.
In days of yore (1920 – late 1960’s in most cases) , water softeners were installed in homes as “Portable Exchange” devices. Once exhausted, they would be removed from the home or business, and then exchanged with another tank. Thee exhausted tank was recharged or regenerated at a central location.
This portable exchange method was only feasible until transportation costs became prohibitive, and innovative manufacturers developed ways to manually regenerate water softeners “in-situ” – in place.
Manual regeneration was performed by regenerating with table salt once the water started feeling hard or on a predetermined schedule. the system would be valved out of service, the top of the tank would be opened, salt inserted, valved back online, and then rinsed through a household fixture.
In the late 1960’s, innovators like Erie Controls developed methods for actually regenerating softeners without opening them up. The “semi-automatic” timer is still sold today and is very effective for window washing, coffee house, RV, and other applications.
The semi-automatic control brought great convenience to homeowners, who now no longer had to deal with manually cleaning their systems. They now had to just fill a “brine tank” and clean their system when they felt it was appropriate. This was ground-breaking technology that made life significantly more convenient and provided end-users with more uniform softened water.
Semi-automatic regeneration continued until the 1970’s when Erie controls developed the first time-clock (day-timer)-based control. This control provided homeowners with the ability to schedule the regeneration of their water softener on an hourly schedule. While the hourly schedule was innovative, many homeowners were confused with a control that calculated “hours until regeneration”.
In 1978, Erie developed a controller that would actually display the time of day and allow the homeowner to choose a designated regeneration time that was intuitive and easy to understand. Homeowners could now schedule the days on which their water softener would clean itself, and at what time the cleaning would occur. This was described as a “fully-automatic” control in the industry.
Automatic controls were extremely effective, giving a homeowner total control over their softening efficiency and performance, but there was a movement afoot to create an on-demand water softening control that would clean based on water consumption and not on a calendar schedule. Erie Controls developed the 541 electronic controller in 1983, revolutionizing the industry with a programmable logic controller (PLC) that would monitor and control the regeneration of a water softener. Fleck followed suit shortly after with a mechanically metered control (5600 Econominder) that was very reliable and is still in use today throughout the world.
Metered controls were programmed with a total capacity (gallons), and a reserve capacity (gallons) so that they could “intelligently” control when the system would clean. The reserve was a predicted volume of daily water consumption that would always remain available for use. At the designated regeneration time, the control would observe the remaining capacity and then determine if it was greater, equal to or less than the remaining capacity. If the remaining capacity was greater than the reserve the control wouldn’t clean. If the capacity remaining was equal to or less than the reserve then it would initiate a regeneration to ensure an uninterrupted supply of softened water.
The two industry powerhouses separately developed their technologies, with Erie focusing on electronics in Europe, and Fleck focusing on mechanics. Other players like Culligan, Ecowater, and Kinetico introduced their metered controls, and soon the industry at large began to drift towards metered controls.
Innovative dealers and manufacturers began evaluating the nature of metered controls and realized that the traditional “reserve” approach of guesstimating an average daily water consumption was lacking. The traditional approach was to estimate (guess) the family’s average daily consumption and then input that as the “reserve” into the water softener.
Fleck was first to market with a “variable reserve” control on the 6600 and 6700 electronic controls. The variable reserve control enabled improvements in functionality and efficiency, since the reserve was no longer fixed. This variable reserve ensured that if household water consumption decreased (someone leaving the home) or increased (new additions to the family or guests) that the control was able to accommodate.
Autotrol’s attempts at control electronics were very disappointing, and Erie stayed behind the curve during numerous acquisitions and mergers in the 1990’s.
There was a vacuum in the marketplace for an intelligent control that took more into account than just hardness, water consumption, and a day override. One inherent weakness with reserve-based systems is that the household might not necessarily use all of the reserve capacity on the day before the system regenerates. For example, the average daily consumption is 600 gallons, so the system adjusts itself to a 600 gallon reserve. The 600 hundred gallon reserve ensures that the household has enough water for the system to regenerate the next morning without running out of softened water. If the household only uses 100 gallons on that day, then 500 gallons of reserve capacity is wasted. Clearly, variable reserve was not enough.
Autotrol came through with a proportional brining method that regenerated the system every single day and only dispensed the exact amount of salt required for regeneration that day, derived as a proportion of overall system capacity. This approach works well on upflow (counter-current) systems but has problems when brining downflow (co-current). A daily cleaning also tends to waste backwash water, so the industry demanded more…
Fleck introduced it’s variable brining algorithm on the 6700 ET controller in the mid-1990’s which was a very effective approach, especially on upflow systems. Fleck’s variable brining approach considered the following data when making regeneration decisions:
- Resin volume in cubic feet
- Brine line refill flow rate (BLFC)
- Brine dosage per cubic foot
This variable brining approach was extremely effective in maximizing brine efficiency during regeneration.
In the late 1990’s we noticed a dramatic decline in water quality throughout the Western States, requiring the adoption of high kinetic resins that respond very quickly to waterborne ions and can remove metals in addition to calcium and magnesium hardness.Research from resin manufacturers as well as field studies showed that resin efficiency decreases over time and in the presence of metallic ions. It became evident that there was a lot more to producing good soft water than just shoving industry-standard resin into an industry-standard tank and brining it with salt.
I approached all the major manufacturers to provide the algorithm that would later be known as fractional brining. Corporate politics impeded speedy adoption and was I finally forced to introduce my own software algorithms to integrate into the control valves of my then employer.
Fractional Brining takes the following data into consideration when making decisions on when and how to clean the softener, conditioner, or filtration system:
- Water Hardness level
- Ferrous Iron level
- Resin Type (K-factor)
- Resin Volume
- Brine refill rate
- Brine concentration
- System Age
- Average Daily Water consumption over the last 30 days
- Average Daily Water consumption over the last 365 days
- Number of manual regenerations in the the last 30 days
- User-controlled “efficiency” level
Fractional Brining ensures that the benefits of advanced resins can be leveraged, and that a water quality improvement system can be as efficient as possible.
In addition to addressing efficiency and water quality, fractional brining software ensures that a system is able to flush at least once a week to protect from accumulation of Heterotrophic Bacteria (HPC’s) in the media bed without wasting salt; if no water is used between scheduled regeneration overrides, then no salt is used either. On certain models, the system can “Deep Clean”, which is an automatic adjustment of backwash and ion exchange cycles based on the time elapsed, or number of regular cleanings that have occurred. Some models also include “Bridge Buster” algorithms that help to break up brine tank salt bridges through intelligent staging of cleaning cycles.