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Natural Pools – The Pros & Cons of Going Au Naturel

We look at the Pros and Cons of Natural Pools and discuss the chemistry & science behind NSP’s. With guests Rudy Stankowitz & Allen Schnaak.



Natural Pools - The Pros & Cons of Going Au Naturel - Are NSP's (Natural Swimming Pools Safe?)

The chlorine shortages we’ve been facing this pool season has consumers looking for viable alternatives to a traditionally chlorine sanitized pool. Natural pools first started as a trend a few decades ago in Europe and over the past few years have slowly been gaining traction in the United States and Australia.

A Natural Pool BioNova built in Germany.

What is a Natural Pool?

A natural swimming pool typically doesn’t use chlorine for sanitization. NSP’s use plants to filter the water chemistry naturally, without chemicals. In most applications, the swimming pool is divided into two different sections: an area for swimming, and a dedicated regeneration zone with living plants that feed hydroponically on the water.

How does a natural pool work?

The water itself is naturally filtered by microorganisms through biological filtration plant life in the regeneration zone. The water is cleaned and filtered as it passes through the regeneration zone, and then back into the swimming area. A pump allows slow moving water to passively filtrate and the movement helps prevent mosquitos from breeding.

Small aquatic animals, such as microscopic algae-eating daphnia, snails, and amphibians, will typically colonize the regeneration zone of a natural pool environment over time.

This photo of a natural pool appears to have the blue water U.S. consumers expect in a chlorine pool.

Natural Pools Are Becoming More Popular

Allen Schnaak, Vice President of Business Development for BioNova Natural Pools thinks this could actually be a pivotal moment to introduce the pool industry to a new way of looking at how to filtrate and treat bodies of water. Recently Schnaak spoke with the Wall Street Journal touting the virtues of a chemically independent pool environment, and suddenly folks have begun to seriously pay attention.

BioNova is one of a handful of companies around the United States that are specializing in building NSP’s (natural swimming pools). Schnaak, who has appeared in numerous articles on the subject, has been working to educate consumers as well as the pool industry about the benefits of bio filtering swimming pools without the use of chlorine or other chemicals.

The Value Proposition of owning a Natural Pool

“Biological filtration in a natural pool has the same objectives as chemical applications.” said Schnaak who has a long history in the pool industry and worked on the chemical side before embracing natural pools. “The purpose of adding chemicals to the pool,” continued Schnaak, “is the same purpose of biological filtration and that is to reduce and suppress the opportunity for pathogens to exist and thrive in the water.”

“We’re seeing this play out in natures backyard in Tampa Bay right now with the red tide influenced by a greater amount of nutrients than the ecosystem can consume which gives these pathogens an opportunity to thrive.” said Schnaak referring to a toxic algae bloom which has ravaged marine life and killed millions of fish over 100 square miles of Florida coastline.

The Red Tide has devasted many parts of the Florida Coastline this season. - Photo Credit: Edwina Pickles/The Sydney Morning Herald/Fairfax Media/Getty Images
Photo Credit: Edwina Pickles/The Sydney Morning Herald/Fairfax Media/Getty Images

We’ve seen plenty of articles discussing natural pools, how they work, and why consumers should consider building one. In my discussions with Schnaak prior to our interview, I asked him if he would be willing to have a frank and open conversation with Rudy Stankowitz who has openly expressed his disdain for natural filtration and disaffectionately refers to NSP’s as “ponds”. Schnaak jumped at the opportunity to address Stankowitz one on one on the Pool Magazine podcast.

The timing for Schnaak to pitch the value proposition for natural pools couldn’t come at a better moment. With the current shortages consumers are facing, plus a new emphasis on eco-consciousness, the opportunity is there for bio pools to pick up enormous traction. The problem however, is winning over the pool industry. Folks like Rudy Stankowitz, one of the foremost experts in swimming pool algae have their own ideas about how viable bio filtration truly is in comparison to using chlorine.

Girl enjoying a dip in a natural pool environment

Advantages of Natural Pools

  • Natural pools are eco-friendly and can work in a range of different climates.
  • Natural pools do not rely on chemicals like chlorine to sanitize the water in the pool.

Disadvantages of Natural Pools

  • Require larger lot sizes to build essentially two pools, one for swimming and the other to function as a regeneration zone.
  • Water color and clarity is not identical to that of a chemically treated chlorine pool.

“It is not necessary to chemically treat a pool in order to make it viable and healthful for someone to swim in.” said Schnaak, “Our opportunity in the market has certainly increased, and we’re definitely anxious and interested in getting more of our pool industry cohorts to consider that there is a viable option outside of chemical treatment.”

An Opportunity To Convince Non-Believers

Stankowitz, who recently authored a new book “How To Get Rid of Swimming Pool Algae“, has appeared on the Pool Magazine podcast when we discussed the chlorine shortages and the trajectory this years supply chain would take. Extremely knowledgeable when it comes to swimming pool chemistry, Stankowitz is a 30 year veteran and CEO of Aquatic Facility Training /

Allen Schnaak goes head to head in a discussion on NSP's with Rudy Stankowitz, Algae Expert
Allen Schnaak and Rudy Stankowitz went head to head in a thought prevoking discussion about the pros and cons of natural pools.

We felt that having Schnaak and Stankowitz go head to head would make for a compelling dialogue and we weren’t wrong. Stankowitz’s expertise and viewpoint create the perfect counterpoint for a dynamic conversation about natural pools. Schnaak and Stankowitz go way back and have a mutual respect for eachother, but currently they sit on opposite sides of an important issue. Whether natural pools are as safe to swim in and ultimately as cost feasible as chemically treated pools.

Are natural pools as cost efficient to build and ultimately maintain as traditional chlorine inground pools?

“Really, I’m not a fan” said Stankowitz, “I am a fan of algae being used for other things. Things are progressing, there’s been a lot more fuels. Even in waste water treatment, algae has become a major player. My problem is that this is basically a pond and it looks like a pond.”

“As long as anything living gets into it, there is going to be constantly things that are introduced to that body of water that are not able to be eradicated quick enough that it can’t cause a potential problem for human beings. The follow up to that which is just as heavy is water clarity. We know that 10% of all drownings are attributed to cloudy water situations.” said Stankowitz.

Schnaak says that people need to rethink the notion that natural pools are green messy bodies of bond water.

“The preconceived notion that all natural pools are green messy bodies of pond water are just a misimpression. We’ve done pools with water clarity easily down to 12 feet. I’m a big believer in safe water environments. In fact the swimming pools we design are built to ICC and ANSI standards. The vessels are safe, and to that point water clarity is not an issue.” said Schnaak.

“If your only experience with a natural pool is looking at a green cloudy pond, then there’s a greater exploration of opportunity. We’ve got a 20,000 square foot public pool up at Webber Park with a 13 foot diving well that is totally clean with a 500 person bather load.”

Webber Parks Natural Pool in Minneapolis
Webber Park’s Natural Pool in Minneapolis
  • Swimming pool is 21,000 sq. ft. (500,000 gallons water)
  • Regeneration basin is approximately 16,250 sq. ft.

“The Opportunity Is On You”

Stankowitz replied “We’re giving you the benefit of the doubt. The opportunity is on you…” in reference to changing perception in the market that not all natural pools are ponds. “I’ve only seen the pictures that people put out there and honestly I have never in any magazine, in any post or anywhere seen a natural pool that is not green. So the opportunity for education is on you. I’ve known you a long time and I believe you.”

Natural Pools utilize a regeneration zone to biofiltrate water back into the pool.

“From the standpoint of the industry and where it is in the United States, natural pools are not nearly as prevalent in the U.S. as they are in Europe. 16% of the recreational water in Europe are natural swimming pools. Probably less than 0.3% in the U.S. can be termed as a natural pool.” said Schnaak.

“The opportunity for helping the industry recognize that this is a viable method for maintaining recreational water is on us, you’re right; and it’s really up to the market as well. There certainly is an increasing interest by those looking for more sustainable options for pool care.” continued Schnaak.

“The opportunity for nutrients to be put into a body of water is going to be defined by the footprint that it has in the landscape.” said Schnaak. “As any pool is constructed it’s always built so that it does not allow surface runoff to enter the pool.”

Debating The Safety of Natural Pools

“We do know that with a given square footage there is an anticipdated amount of environmental depositions of nutrients that are constantly bombarding the pool.” said Schnaak, “In a chemical environment they are referred to as contaminants because everything that can be oxidized, reduced or killed has to be killed as soon as you begin taking out the beneficial microbial life that would be consuming it.”

“I don’t necessarily know that I agree with you that if you have diatoms present in a body of water that you will not see cyanobacterial biofilm.” said Stankowitz.

“I understand the process that we’re feeding the water with phosphates and silicates so that diatoms can outgrow and use up the nitrates so that nothing else can have them therefore they don’t grow. In theory, that works great. The problem is just like there are carbon fixing diatoms, there are nitrogen fixing cyanobacteria so you will still have these biofilms, and these biofilms do harbor many other disease causing organisms such as Legionella and Naegleria fowleri (the brain eating amoeba),” continued Stankowitz.

“I’ve done extensive studies on black algae which is cyanobacteria and in those biofilms I’ve found diatoms living happily. It’s not an incompatible relationship if you have the right diatoms and the right cyanobacteria.” said Stankowitz.

“It’s interesting that diatoms are a participant,” responded Schnaak, “they are part of the population, but they are not the only microbial life. When you consider phytoplankton, zooplankton, the entirety of population of beneficial bacteria that has been specialized for the nitrogen reduction cycle.”

Schnaak suggested that copepod zooplankton like Daphnia which grazes in fresh water environments on cysts like Cryptosporidium and Giardia and harmful viruses to which Stankowitz responded with a few different “what if” scenarios. “To your point about Daphnia, it feeds til it explodes and releases that back into the water. That’s also the problem we are having with the red tide. Daphnia doesn’t last long enough to contain it all and then if it’s consumed by an animal, a person can eat that animal, or it can be defecated or released into the atmosphere and that could make it’s way back into the pool.”

Webber Park Natural Pool built by BioNova Natural Pools

Changing Perception That Chlorine Is King

“I think the major challenge for you,” Stankowitz said to Schnaak, “is chlorine does kill these things. We have proof that chlorine kills those things. What we need then if this is true, if this system takes all these things out, we need to get that research out and make that common knowledge because that’s how you gain more acceptance in the pool industry,” continued Stankowitz.

Schnaak agreed and said that as a member of the council for the Model Aquatic Health Code that they’d begun participating in an ad-hoc committee for the evaluation and potential implementation of biological filtration for public aquatic venues. Schnaak agreed there is much that is still misunderstood about natural pools and that each project has to account for the specific environment, size, bather load and unique characteristics.

No One Size Fits All Solution

Natural swimming pools are very dependent on maintaining ideal conditions for the plant life which bio filtrates and allows useful organisms to thrive. “There isn’t a one size fit’s all, neither is there in chemical applications. There’s not a pool out there where you couldn’t find a pathogen or organism living in that environment. The presence of chlorine does not indicate a sanitized environment.” said Schnaak.

Ultimately, Stankowitz still had serious questions pertaining to how long harmful pathogens can survive in the biofilm in a natural pool and insists that chlorine is still the most reliable solution for sanitizing pools. Schnaak is adamant that the system that BioNova has created is capable of biologically filtering swimming pools to the point where they are viably safe swimming environments.

Stankowitz said that while he’s open minded to the concept of natural pools, he needs to see more conclusive research on the subject before he’s swayed from using tried and true chlorine sanitization methods, which prompted Schnaak to invite him and as well as others interested in learning more about natural filtration methods, to seek out more information on the Association for Swimming Ponds and Natural Swimming Pools website.

Natural pools and ponds have become increasingly popular with the recent chlorine shortages

Why Have Natural Pools Been Slow To Catch On In The U.S.?

While natural pools are becoming increasingly popular in Europe, there is no denying that they have a nominal marketshare in the United States. In this humble editors opinion, there are several impediments towards more acceptance beyond those early adapters.

One is the public perception that all pools must have crystal clear blue water. Another are the requirements for constructing a natural pool. Given the need for an additional regeneration zone, most natural pools are typically built on larger sized lots. The initial build and configuration cost for a natural pool is also much more than your typical inground pool. There is definitely some give and take in terms of initial cost concerns versus ongoing chemical costs.

There are also a good portion of consumers that while aware of natural pools, have a tendency to believe a popular misconception; which is that NSP’s maintain themselves. Natural pools, just like chemically treated pools still require routine maintenance and to some extent even more attention than a chemically treated pool in order to ensure a harmonious water environment.

Still Schnaak remains a champion for the bio filtration cause and says a growing percentage of environmentally conscious homeowners yearn to go chlorine free. As such, he will continue to facilitate and fan that interest to generate more excitement and awareness about natural pools.

Q&A Fact Sheet About Natural Swimming Pools – NSP’s courtesy of Allen Schnaak – Vice President of BioNova Natural Pools

Listen to our entire interview with Allan Schnaak and Rudy Stankowitz on the Pool Magazine podcast.

Featured Photo Credit & Article Photo Credits: BioNova Natural Pools

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Editor in Chief of Pool Magazine - Joe Trusty is also CEO of, the leading digital agency for the pool industry. An internet entrepreneur, software developer, author, and marketing professional with a long history in the pool industry. Joe oversees the writing and creative staff at Pool Magazine. To contact Joe Trusty email or call (916) 467-9118 during normal business hours. For submissions, please send your message to

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Claffey Pools Acquired by Riverbend Sandler Pools



Claffey Pools Acquired by Riverbend Sandler Pools

The pool industry has seen a spate of recent acquisition announcements. The latest, being the recent acquisition of Claffey pools by Riverbend Sandler Pools. Backed by Chicago-based Concentric Equity Partners, they are continuing efforts to consolidate the swimming pool construction and maintenance industry in the Dallas-Fort Worth market.

The acquisition agreement was signed on December 31, 2021 but only made public on Thursday. Full details about the exact terms of the deal were not disclosed.

This marks the third major pool builder purchased by the holding company, after acquiring Pulliam Pools back in November. The acquisition of the Fort Worth-based firm made it one of the nation’s largest pool construction companies.

This recent acquisition of Claffey Pools which is ranked within the nations top pool construction companies with about $32 million in reported residential construction revenue in 2020. A builder of high-end inground swimming pools, Claffey’s average pool project costs around $142,000.

Riverbend Sandler intends to make considerable advancements by acquiring existing service and maintenance companies, in addition to focusing on construction. Consequently, they hope to become a key service provider in the state’s pool service and maintenance sector.

This in itself appears to be a key decision point for the Claffeys who are looking to expand their pool service and maintenance divisions. Last year’s Texas Pool freeze caused unprecedented amounts of damage across the Lone Star state and saw Claffey perform over 1,000 repairs as a result.

In regards to any restructuring of the organization, the Claffeys, along with their 95 employees, will remain with the company. Riverbend Sandler has announced its intentions to continue its expansion. It will continue to concentrate on Texas, for the time being, looking seriously to expand into the Austin, Houston, and San Antonio markets after having established the predominant marketshare in the Dallas area.

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GENESIS Announces Newest Platinum Sponsor: Pool Magazine




GENESIS Platinum Sponsor - Pool Magazine

(Alexandria, Va.) – GENESIS is pleased to announce its newest Platinum Sponsor, Pool Magazine. The GENESIS sponsorship program showcases companies that are dedicated to the highest standards of best practices, quality, and ethics in the pool and spa industry.

“We look forward to collaborating with PHTA and expanding our relationship as a Platinum Sponsor,” says Joe Trusty, CEO & Editor-in-Chief. “We are excited for this next chapter and look forward to making a positive impact on the industry.”

As a Platinum Sponsor, Pool Magazine will have the opportunity to maximize its brand visibility, connect with thousands of engaged industry professionals, and unlock valuable opportunities.

“We are delighted to add Pool Magazine to our distinguished list of Platinum Sponsors,” says Janay Rickwalder, Vice President of Communications and Public Relations of PHTA. “Pool Magazine has everything we look for in a partner: quality services that can benefit our members, an understanding of the importance of continuing education, and a finger on the pulse of industry trends. I am excited for this collaboration and to working together in 2022.”

For more information, please contact Janay Rickwalder, PHTA’s Vice President of Communications and Public Relations, at or 703.357.3918.


About the Pool & Hot Tub Alliance 

The Pool & Hot Tub Alliance (PHTA), a non-profit organization with nearly 3,500 members from around the world, was established in 1956 to support, promote, and protect the common interests of the $36.5B pool, hot tub and spa industry. PHTA provides education, advocacy, standards development, research, and market growth to increase our members’ professionalism, knowledge and profitability. Additionally, PHTA facilitates the expansion of swimming, water safety and related research and outreach activities aimed at introducing more people to swimming, making swimming environments safer and keeping pools open to serve communities. For more information, visit

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Pool Contractors Gift New Pool To Grandma After Disaster



Pool Contractors Gift New Pool to 80 Year Old Grandmother in Indianapolis

A group of pool contractors are the answer to one homeowners prayers. For years, Kitty Smitth, an 80-year old resident of Indianapolis, had dreamed of having an inground swimming pool for her 29 grandchildren and great-grandchildren to enjoy. Smith had just recently used her life savings to purchase a home and property in South Indianapolis that she was hoping would allow her to finally realize those dreams.

Smith acknowledges that the home she purchased needed a lot of work inside, but held out hope of enjoying the backyard with her family. For Smith and her grandchildren, the backyard pool meant a safe haven from the dangers of the pandemic that was sweeping across the country last summer.

“They were here, swimming and playing. I can’t tell you how great that was. This has just been my dream my whole life,” she told reporters.

Smith’s pool collapsed after a snowstorm this February. Photo Credit: WTHR

Future summer dreams would be put to an end this February when a winter storm caused her pool to collapse into a heap of disintegrating concrete and collapsed fiberglass walls. Smith was horrified to find that her backyard pool had collapsed in on itself in the night. “My whole body just started going numb and shaking. I couldn’t believe what I was seeing,” she told reporters.

An engineering report was conducted to determine the cause of the failure. Analysis determined that a leak may have contributed to its collapse. A new pool cover, which had just been installed, combined with the inadequate water level in the pool may have contributed to adding stress on the walls of the pool.

To add insult to injury, Smith quickly found out that her homeowners insurance would not cover the damage. Despite being a customer of the same company for over 40 years and having a policy that includes the replacement cost of an inground pool, her insurance company refused to pay a cent. They claimed her policy excluded any leak in the structure of the pool.

Smith was faced with an impossible problem. The cost of installing a new inground pool would be at least $60,000 plus an additional $20,000 for hauling away the debris from the old pool that had collapsed. “I just put everything into my house”, Smith told reporters, indicating that she didn’t have the financial resources to rebuild the pool. She stated that she felt like her insurance company had left her high and dry.

Smith contacted investigative reporters and discussed her problem with them. The reporters shared her story with some folks they knew in the pool industry that could help lend a hand. Ultimately, eight separate Indiana companies came together headed up under Automatic Pool Covers owner, Michael Shebek. Shebek pooled his resources and network to help put together a team that will help rebuild Smith’s backyard.

What is truly incredible about this story is that although some of the companies on this list are competitors, they are all united in the single goal to help one local resident recover the usage of her pool.

Shortly before the Thanksgiving holiday, Smith was greeted with the surprise of a lifetime. The contractors who have agreed to rebuild her pool at zero cost, showed up at her house along with the 13news team to break the good news. Overwhelmed with emotion, Smith hugged them all and said “I don’t know your names but I know your hearts,” telling the contractors, “I love you.”

A team of local pool contractors has vowed to help Smith rebuild her pool. Photo Credit: WTHR

Smith will hopefully have a new pool to enjoy with her grandchildren this summer. The contractors have all assured her that the unsightly mess in her backyard will be removed and a new pool installed. The entire cost of the project is estimated to cost approximately $90,000.

“Just no words. There aren’t words big enough to thank everyone,” Smith said. “I’m just so thankful.”

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