I will be making a closed water loop for cooling purposes, that shouldn't require any servicing for at least 4 years.
I have been told never to use pure distilled water in such a loop (by chemical coolant manufacturers), because of the ion-hungry quality of distilled water and a pH of 5.6 because of dissolved CO2. But somehow I can't believe the water will damage the aluminium cooling block to such an extend that it will cause it to leak.
The 250 ml of in the system water will be approx. 55°C, and the water will come in contact with flexible PVC tubing, and acrylic. Considering this system being free of debris and sterile, and a durable water pump being used, what could be said about its longevity?