As I became aware of the concept of
Natural Swimming Pools for me the next logical step, was
exisiting concrete swimming pool conversions. With some 4 million
chlorine pools in the U.S alone, surely some swimming pool owners
could appreciate the idea.
Gradually turning into my pet project, I set
out to design a way to convert pools to natural filtration. chlorine
free with no chemicals of any kind, maintaining crystal clear, fresh
A well designed system, just as with any natural
swimming pool, should easily beat any municipal “drinking” water
standards. It may require a little more elbow grease especially in
the first year or so, but truly shouldn’t be much more work than the
traditional ‘chemical bath’ of a chlorine pool. A true chlorine
It requires constructing a basin equal to 5-10% of the pool volume(1
cubic foot=7.481 gallons), and about 4 feet deep. Build along one
side of the pool with a smaller second basin up on your existing
pool deck. This will allow for getting around the pool as long as
the smaller basin is built for walking on its outer edges.
The basin can be built of concrete,
adobe/stucco , stone mortared, or even wood. You can
be very creative with shape and style. I do recommend lining with a
regardless. There will be less chance
of mineral leaching in the water, plus a pond liner will go years
longer without maintenance. You never want to disturb a filter basin
that is working properly. I’m talking about the possibility of
never, or almost never, cleaning out the filter other than seasonal
plant thinning. If it ain’t broke, don’t fix it.
Fill the basin with some sort of inert gravel, maybe
half inch size, haydite or even cinders. Haydite and cinders are
good because of their incredible surface area for beneficial
bacteria to adhere to. Bacteria that is required for
Biological Filtration. Many water gardeners may cringe at the
idea of using cinders due to what they’ve seen as a ‘clogging’
problem. Often this is because of large fish loads that the filter
simply cannot keep up with. Swimming pool conversions on the other
hand will never deal with this level of nutrient build up and should
easily digest what is present. After all a pool starts with clean
water so it’s only a matter of maintaining water quality.
Divert 2/3rds of the water away from the existing
plumbing, to percolate up through the large basin. From there the
water pours out and down into the second smaller basin(adding
oxygen), and finally pouring back into the pool. Functioning much
like an aquarium 'pour-over' filter.
Plant a diversity of
Aquatic Plants especially aquatic mint for its antibacterail
properties and reeds. This will finish the Nutrient Cycle. Leave everything from the original pool intact.
The existing pressurized filter will help especially with its
ability to backflush.
UV Sterilizers can and probably should be used for further
filtration. Also, 'Pebble Tech' pool plastering is recommended for
its overall more natural feel. This is when a pool is covered with
small polished stones, all the rage these days.
Additionally, when deciding on placement of the
filter basins be aware of the placement of the skimmer. The skimmer
being the most important peice of the filtering process(everything
floats first)so good circulation is escential. Lastly, bacteria
cultures can be used within the pool water and/or the filter basin
to 'seed' the biological filter. Not escential but will add
diversity and speed up the process.
In the end not only will you have a naturally
filtered swimming pool, but also a two-tiered waterfall and gorgeous
water garden to be enjoyed year round.
Hope I did a decent job of explaining this still
experimental concept. I would like to add that after discussions
with Dr. John Todd of
Ocean Arks International and Michael Littlewood, the true
pioneer in the development of natural swimming pools throughout
Europe and Authur of
"Natural Swimming Pools: Inspiration For Harmony With Nature" ,
I have complete faith in the concept. Offering a true chlorine
alternative. No more Chlorine Poisoning, Chlorine allergy, chlorine
irritations or cancer risk. Pure chlorine free pool swimming.
If you're planning a pool conversion please keep me
posted and don't be afraid to "Ask Me Anything".