Rainfall changes the composition of your pond water over time. Since rainwater does not contain any minerals, your pond water becomes softer and softer (the hardness decreases). As a result, your pond inhabitants may lack vital minerals (calcium, magnesium, etc.) and the pH of your water will also fluctuate more and more throughout the day. By adding JBL StabiloPond Basis regularly, you add lost or depleted minerals to your pond water and stabilise the pH.
You can find additional information about the product and a detailed description here: JBL StabiloPond Basis .
For more on water stability and pond care during heavy rain, see: Agua de lluvia .