[gglockhart]

I use commercial ice machine cleaners which are mostly phosphoric acid but sometimes other acids are added such as citric, hydroxyacetic acid, and other acids.  The MSDS sheets of these products shows the phosphoric acid content as > or < of percentages but rarely shows the % of other acids.  Some ice machines have stainless steel evaporators which are tolerate to more and stronger acids but other evaporators are plated and require ice machine cleaners that are labled as metal safe or nickle safe.  I have been trying to find out that since phosphoric acid is the main acid in regular and in metal/nickle safe ice machine cleaners what determines if it is metal/nickle safe or not.  My guess is that the acid content and mixing directions provides for a weaker solution of acid for the metal/nickel safe cleaner but I have not been able to get this confirmed.  I bought a pH meter and want to know if this could be a reliable method to determine this?  If I mix each different brand and type of ice machine cleaner as they are labled and measure the pH levels would the resulting readings be an accurate indication that the difference in the regular and the metal/nickel safe cleaner is the acid strength or not? I want to know if the difference in regular and metal/nickel safe cleaners are acid strength's or added chemicals to protect the plating.  The metal/nickel cleaners usually require mixing 5 ounces of the cleaner with each gallon of water but the regular cleaners usually require around 2 ounces to each gallon of water. Also could the pH meter be used to determine which brand of ice machine cleaner has the highest acid concentration right out of its bottle?  I would appreciate any feedback for this. Thank You

[x12yhp]

You could use the pH but you rely that the concentration of other things remains roughly similar. I have not looked into the area in depth but the products we formulate and sell as 'stainless steel safe' are phosphoric based. They only start to become otherwise when you have mineral acids (other than nitric). If a product is thickened and is phophoric based, there is a reasonable chance that someone might add a bit of hydrochloric because it makes thickening easier. If you don't you often need to add other things (hydrotropes for instance) to attain the desired viscosity.