
Why is a natural swimming pond special?
A natural swimming pond works without chemicals. Our main goal is to filter out the nutrients in the water in order to impede the growth of algae. We do it like this:
- The (potentially nutrient-rich) water is being taken from the bottom of the swimming basin with the help of 4 large sediment traps. You can not feel the water movement, but it is there.
- Very slowly, but constantly the water is being moved through the water plant basin.
- Afterward, the water goes through a series of foam filters and it’s being treated with a UV lamp before being released again into the pond

We always wanted a natural swimming pond
The garden and the view from the garden towards the fortified church were the main reasons for us to choose Alma Vii as the basis for our Guesthouse. Right from the beginning, we knew we wanted a natural swimming pond in the Alma-Via Guesthouse garden.




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Operating a natural swimming pond is not without challenges
Regular maintenance includes
- checking for and removing, objects thrown in by kids (parents: don’t allow your kids to play around the pond alone!!)
- checking for dams built by kids that prevent the water from flowing back into the pond and consequently emptying the pond over time (parents: see above)
- catching leaves etc from the surface with a catcher
- brushing natural, sunken dirt, aka “nutrients”, into the middle of the swimming area. There we have 4 sediment traps that help move these nutrients toward the filter plant basin
- brushing slippery plant growth from the steps and the kids’ area entrance
- every few weeks cleaning the foam filters
- cleaning out the sediment traps from time to time
Now you see that maintaining a pond includes more than what the casual observer might think.
On top of the regular maintenance, we also have to react to anything else such a pond can encounter
“Spontaneous Accompanying Fauna”
Snails
One year we had a snail infestation. Or, politically correct: “spontaneous accompanying fauna”. We are talking about hundreds of them. Three times they ate all the underwater plants in the filter basin. We had to always bring new filter plants. It didn’t help the water quality that year. All we could do was collect them by hand and with the catcher. Luckily these didn’t affect swimmers.

Fish
We opted against having fish in our natural swimming pond.
But as Jeff Goldblum said so nicely in Jurassic Park: “Life finds a way”. In our case, we were first mystified when we observed small Koi Karps populate our pond. Later, other fish species followed. The fish eggs probably came with the plants we brought from a (Koi) fish pond not far away.
Fish bring their own set of problems to the swimming pong
- Nutrients. Let’s call it nutrients. Fish add nutrients to the pond that the filter wasn’t dimensioned to deal with.
- Sediment movement. Fish are looking for food inside the sediment and therefore stir up the water and muddy it more than it would be otherwise.
In conclusion, fish are pretty to look at. But they don’t help water clarity. We gave up on not having fish. Eventually, we probably have to add another filter.
Building the pond presented some challenges
Challenges encountered
Building a pond requires a serious investment of time and resources. It is a long way from planning to the final product. The challenges we encountered:
- We started too early. There were already excavators on the property during the building phase. So we told them to dig out the hole for the pond. But then we had to focus our efforts back on our main project. That left an ugly hole in our garden for a long while.
- The excavator drivers couldn’t create the shape we wanted. They also couldn’t create the profiled steps inside the hole. They also dug too deep.
- Over time the sides kept caving in, making the final pond bigger than anticipated.
- Eventually, despite our hopes to get around it, we had to form the steps and inside walls of the pond with the help of walls.
Water fun before the finished build

