Excellent point, Robert. I never considered that, but I bet you’re absolutely spot on.
The acid rinse I use is Stronghold NPS which has a mixture of Nitric, Phosphoric, and Sulfuric acid. I am trying to find the percentages of each but so far no luck on retrieving the MSDS for this product. However it is similar to Learacid marketed by Loeffler which we used at the brewery I worked for. It works well and I got it at a dairy supply store for about $50 for a five gallon container (I only need about 12 ml in a couple gallons of water). It will last me forever! I have also given some to some of the locals to acid rinse their stuff.