According to Focustronic, it is advisable to replace the following parts to maintain an accurate and properly functioning Alkatronic.

This set contains the following parts:

• 1x internal hoses for pump A (guideline is to replace every 6 months, based on an average measurement frequency of 6 measurements per day)
• 1x internal hoses for pump C (guideline is to replace every 6 months, based on an average measurement frequency of 6 measurements per day)
• 1x internal hoses for pump B (guideline is to replace every 6 months, based on an average measurement frequency of 6 measurements per day)
• 1x internal hoses for pump D (guideline is to replace every 6 months, based on an average measurement frequency of 6 measurements per day)
• 1x microfilter (guideline is to replace every 6-8 months)
  
  

Replacing the parts is clearly explained in the product manual and can be found on the Focustronic website -> support.

It is also advisable to replace the external hose every 6-8 months, but for different installations these hoses must be ordered separately in the desired length and the pH probe must be calibrated every 6-8 months.