Frequently Asked Questions

Building a Natural Swimming Pool is a complex process that should be professionally engineered, designed, and constructed to ensure the water is properly filtered and naturally purified. Recent advances in the use of biofilm filters have simplified the natural purification process by eliminating the need for a large planted regeneration zone. With this option, a Natural Swimming Pool is less complex, but it still requires an exacting measure of construction skills best left to a knowledgeable builder.

BioNova® can be engaged to provide a construction plan that, if executed according to design, can yield a beautiful and functional Natural Swimming Pool. However, in order for the pool to be a BioNova® Certified Natural Swimming Pool it must be installed or supervised by one of our licensed builders. This oversight ensures that the final product provides you with years of naturally purified enjoyment without the frustration resulting from poor execution. Contact us and we can discuss the viable options for your project.

A word of caution… misinformation about Natural Swimming Pools (and other topics) is widespread on the internet. “Install a Natural Swimming Pool for $2,000” sounds too good to be true, right? Because it is… too good to be true.

First, recognize that when we use the word “treated” we are simply referring to the conversion of nutrients in the water by aquatic plants and microorganisms through their own unique and varied metabolic processes. A conventional swimming pool refers to these nutrients as “contaminants”. A naturally purified swimming pool nurtures and employs helpful microbes to consume and/or convert these nutrients into energy for their own survival, byproducts for other organisms to metabolize, or waste to be filtered out.

There are two methods for providing naturally purified water.

1. Use a planted regeneration zone (NSP BioSwimPond®)
2. Use a biofilm filter (NSP BioPool®)

Both methods result in naturally purified water by nurturing the growth of microbes and organisms that remove nutrients from the water. The planted regeneration zone will employ a variety of different aquatic plants to create an environment for beneficial bacteria, zooplankton, and phytoplankton to extract these nutrients, whereas the biofilm filter provides a similar environment for the development of the biofilm (an assemblage of bacteria and other microbes living in a symbiotic relationship), to extract the same nutrients. In either case, we are replicating and optimizing natural limnological processes to create an environment that encourages favorable microbes to outcompete less favorable microbes for the nutrients in the water. With proper planning and hydraulic design, we can create beautifully clear, naturally purified water without the use of any chemicals whatsoever.

NSP BioSwimPonds® incorporate the use of aquatic vegetation hydroponically rooted in carefully selected substrates to allow the water from the swimming area to flow through the planted environment. Generally speaking, the biological filter (a.k.a regeneration zone, bog filter, constructed wetlands, etc.) is approximately the same surface area as the swimming zone. So, a 16’x32’ swimming zone (~500 ft²) would require the same amount of area (~500 ft²) for the regeneration zone.

NSP BioPools® incorporate the use of a biofilm filter to purify the water. Depending on the size of the swimming zone, this biofilm filter can be up to 90% smaller than an equivalently sized regeneration zone.

It depends on what “look” you are after. Both biological filtration technologies create naturally purified water, but they have different aesthetics.

A BioSwimPond® provides the aquatic vegetation that many desire in order to create a naturalistic, pond-like environment. The BioSwimPond® typically comes at a higher cost due to the increased area required for the planted regeneration zone.

A BioPool® will look more like a conventional swimming pool. The biofilm filter in a BioPool® is typically hidden underneath a wooden deck. In these cases, access to the top of the vessel needs to be anticipated for seasonal maintenance. Since the overall footprint of the BioPool® is smaller due to the absence of a planted area, the cost associated with a BioPool® is generally less than that of a BioSwimPond® with an equivalently sized swimming area.

Yes – how much you can heat the pool depends on your climate and on the time of the year. BioNova® Natural Swimming Pools tend to be warmer than traditional pools because the biological filter is relatively shallow and acts as a passive solar collector. And “Yes”, technology does currently exist to allow cooling of the pool water if desired. Temperature variations in water occur naturally. As long as the NSP water is not heated beyond the seasonal norms of naturally occurring bodies of water in your climate zone then there isn’t going to be a problem. Recent adaptions of solar heating panels provide the opportunity to heat the pool during the day, or if you want to cool the water, cycle the panels at night when the air temperatures drop. Ask your BioNova® Dealer for details on heating (or cooling) in your area.

Because a BioNova® Natural Swimming Pool’s water is always circulating, mosquitoes are not a problem as they do not breed and lay eggs in moving water. A bigger concern for breeding mosquitoes are potted plant bases, or any place water can gather and remain stagnant.

It depends. Generally speaking, the cost per square foot of a Natural Swimming Pool is no different than the cost per square foot of a conventional pool. However, prior to the use of biofilm filters Natural Swimming Pools did cost more because they required TWICE the surface area (swimming zone + planted regeneration zone), and on average these types of installations started around $100,000. Now, with a biofilm filter doing the biological purification, a typical 16'x32' pool will average between $60,000 to $75,000. Once installed, ongoing operational costs are lower since no chemicals are needed and energy consumption is much less than for a chemical pool.

No, although fish would love to live there. Fish consume beneficial zooplankton, but the biggest reason is that they put an undesirable biological load on the system and are not permitted in the swimming or regeneration zones in order to meet BioNova® standards. One of the biggest objectives in designing and maintaining an NSP is to control the amount of nutrients entering the pool, and fish are large contributors. However, if you really want to have koi fish we can include a separate and isolated fish pond adjacent to but not connected to your Natural Swimming Pool. We can design the finished product to look as though they are all one contiguous system but in actuality operate in totally separate, closed-loop environments. In this case you can have your fish and swim too.

Yes, algae and other phytoplankton species are naturally occurring microbial plant life and the living aquatic environment we are creating relies on the healthy – but controlled – growth of phytoplankton and other producers in the microbial lifecycle. An NSP will always have some algae in it (in fact, even a chemically treated pool always has some algae in it) but green algae is not harmful. We control algae by either using the correct aquatic plants in the planted regeneration zone OR by using a biofilm filter to outcompete the algae for the available nutrients in the pool water. Situations that may cause a temporary algae bloom are related to an unexpected influx of nutrients (e.g., phosphate). One possible contributor to excess phosphate in the pool water is the municipal water source. Derivatives of phosphate products are used in water treatment to limit or control corrosion and prevent scale build up in the water lines. As part of our BioNova® Quality Process, we will test your water supply to determine if it would be suitable for the initial filling of the NSP, and then plan and design the NSP system to handle these phosphates appropriately.

Some maintenance is the same as for a traditional chemical pool. We need to periodically empty and clean skimmer baskets, empty and clean pump baskets, vacuum the pool and clean the filter. Robotic cleaners are available for the task of vacuuming and brushing the pool walls and bottom. The good news is that you will NOT be spending any money on water treatment chemicals. For BioSwimPonds®, water garden maintenance is necessary – removing unwanted plants and debris, trimming and maintaining existing plants, and cutting them back at the end of the season. For BioPools®, seasonal "backwashing" (approximately twice a year) of the biofilm filter is necessary. Note: for those of you with gardens (vegetable or ornamental) the discharge from backwashing the biofilm filter is an excellent natural fertilizer.

In cold climates, the NSP needs to be treated just like any other pool, i.e., the plumbing lines need to be blown out and plugged, and the mechanical equipment needs to be drained. The swimming zone can be covered with a winter safety cover, and a mesh net can be draped over the regeneration zone to prevent leaves and other debris from entering the area. For BioSwimPonds®, the aquatic plants will be cut back and dead leaves will be removed from the regeneration zone. Most native aquatic plants are perennial and will regrow the following spring. Some plants may need to be replaced, but the longer the regeneration zone matures the heartier the plants become.

We do not recommend BioSwimPonds® smaller than 535 square feet in total. For BioPools®, there is no minimum size limit. The biofilm filter can be configured to accommodate any swimming pool, large or small. Consult your BioNova® Dealer for details on correctly sizing an NSP.

BioNova® would be happy to assist during any phase of your planning. We will spend our initial conversations discussing your ideas and design goals, such as:

• Spatial considerations.
• The quantity and ages of bathers who will be swimming regularly.
• What are your outdoor living goals and entertaining expectations?
• Are there landscaping and aesthetic expectations of the pool and surrounding area?
• How deep do you want the pool?
• What activities do you like or want in the pool? (e.g., volleyball, lap swimming, group hydrobics)
• Do you want a diving board?
• How about a suntanning ledge or underwater sitting benches?
• Will this be a part of a long term, multi-phase outdoor environment?
• Firepit, outdoor kitchen?
• What about other water features… stream, waterfall, grotto?

The more we know the more we can anticipate and incorporate your wants and needs into the design.

We have many years of experience working with landscape designers, builders, contractors, architects, and pool companies, and we are comfortable collaborating with all. In order for the Natural Swimming Pool to be BioNova® Certified, we require that a BioNova® licensed builder provide the hydraulics, equipment, technical planning for the pool, and construction.