Hot tub water change
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When should you change the water in a hot tub?
If you search the internet, you will find countless recommendations. These range from changing the water in the hot tub once a month, every 3 months, twice a year, or only once a year. So what is correct? When is a hot tub water change necessary? Every statement is either right or wrong. Because there is no fixed time at which you must or should change the hot tub water. It is completely individual, but necessary at a certain point in time.
There is no fixed water change rhythm, but there is a necessary time
There is exactly one chemically determined moment when you must change the water in your hot tub. That is when the water is "chemically dead." What does that mean? Your water absorbs substances. It dissolves them. Some are already in the water when filling (for example lime, magnesium, certain metals, salt) and others you add yourself to the water, such as hot tub chemicals as part of the hot tub water care. The water in the hot tub can dissolve these, but not forever.
You have to imagine it like a glass of water into which we put sugar. It dissolves. The next spoonful dissolves again. But eventually sugar crystals remain at the bottom of the glass. The water can no longer dissolve the sugar.
The hot tub water has reached its maximum dissolving capacity
And that is exactly the moment when you must change the hot tub water. It can no longer dissolve chemicals either, making them almost ineffective and your hot tub water care very complicated.
How do I notice that I need to change the hot tub water?
You can measure it and you can observe when this moment has come.
- Measurement: The dissolving capacity is measured with the TDS value. TDS means Total dissolved solids. So total substances dissolved in the water. If this exceeds the limit (which you take from the instructions of your measuring device), the water must be changed.
- Observation: With the total saturation of the hot tub water, a special effect occurs that can be observed. The process I call the "champagne effect" shows itself in that the water behaves like sparkling water or champagne. When you turn on the pumps, extremely many air bubbles form (also perceived as very foamy), which hiss and burst at the water surface. It takes several minutes after turning off the pump for the water to become clear again and for all the air bubbles floating in the water to be absorbed or released into the air. Ozone devices usually also produce many more and smaller bubbles.
Conclusion on hot tub water change
If your measured TDS value is too high and/or your hot tub foams strongly when the pump is on, the surface hisses like sparkling water, and the water only clears after a few minutes, then the maximum dissolving capacity has been reached and you must change the water.
Can an Ego3 filter delay the water change?
Hot tub filters generally cannot influence this because they can only filter suspended particles – that is, only UNdissolved substances. However, the Ego3 filter can still extend the water change interval because it also removes 0-40 micron particles from the water. If these remain invisible in the water as with cartridge filters, they slowly rot and produce acids as fermentation products of the decay, which of course dissolve again in the water and accelerate reaching the maximum dissolving capacity.
