The pH Probe is a replacement probe (electrode). Unfortunately these Probes do not last forever as they age through normal use and will eventually fail.
With good care and use (keeping the probe tip wet and cleaning once a month) you will extend its life. The pH Probe has a double junction reference. This gives a longer life than many other pH probes and is a gel filled non refillable probe, so apart from cleaning is maintenance free.
Replace only the pH probe, not the whole meter!
Just like humans, all growing plants need a balanced diet of nutrients (food) in order to thrive. However, your plants will only be able to access these nutrients if the nutrient solution is within a particular pH range.
From a water chemistry perspective, pH plays a critical role in making nutrients soluble. So that they can be absorbed by your plants. Furthermore, growing solutions that are too acidic or too alkaline will not allow your plants to absorb nutrients.
Also, get the basics of growing right by regularly testing pH to ensure that this is always within the right range.
