We frequently get asked about the shelf-life of Hypochlorous Acid, we give steps on how to make it last longer, and have told customers it can potentially last for weeks or longer if those instructions our outlines (detailed in other blog posts). However, we wanted to be able to give a more specific answer, so we are conducting our own test.
On February 24 we made a batch of HOCl at 400ppm. We added vinegar to stabilize the pH at around 5, and immediately after making it, poured it into an empty container and closed it tightly (we used a bleach container that had been thoroughly washed).
On March 4, we did our first follow up, and so far the results are encouraging. We were unable to discern any noticeable change in the pH or the Strength of the HOCl Solution.
We use a digital meter for pH and Chlorine Test Strips to measure the HOCl. The test strips measure 50,100,200,400 and 500ppm, so if their was a slight drop in potency, it would be difficult to tell from those strips. So far, after 10 days, there has been no degredation in the HOCl that we were able to discern.
We will update the test periodically to see how HOCl produced with our Generators hold up as time passes.
3 weeks since the test began, still no ,measurable degradation of the Hypochlorous Acid. pH is at 4.9-5 well within the range of 100% HOCl and Chlroine is still over 400ppm.
We are now going on 5 weeks from when we first created this batch of Hypochlorous Acid. Still no noticeable degredation in the HOCl. pH is still around 5.0 and Chlorine Test strip is still over 400ppm