If the propylene glycol concentration level is too high, what should be added?

When faced with a situation where the propylene glycol concentration level is too high, the ideal solution is to dilute the mixture to achieve the desired concentration. Deionized water is the most appropriate choice for this purpose.

Deionized water has undergone treatment to remove ions, impurities, and minerals that could potentially interfere with the properties of propylene glycol. By adding deionized water, you ensure that you are not introducing additional substances that might affect the balance or effectiveness of propylene glycol in applications such as cooling systems or antifreeze formulations.

Using distilled water could seem like another reasonable alternative since it is also purified water. However, deionized water is often preferred in specific industrial applications for its purity level and lack of ion content.

Tap water, while readily available, contains various dissolved minerals and chemicals that may alter the behavior of propylene glycol, potentially leading to unwanted reactions or efficiency losses.

Antifreeze solution, which typically contains a blend of propylene glycol and additives, would not resolve the issue of high concentration. Instead, it would add even more propylene glycol, worsening the problem rather than alleviating it.

Thus, the addition of deionized water is the correct and most effective method for reducing propylene glycol concentration.