In laymen’s terms, etidronic acid is a fancy name for a bio-phosphate that’s commonly used in water treatments and sometimes cosmetics. It is a chelating agent that can be added to bind substances found in pool water such as calcium, iron, or other metal ions.
What is a chelating agent? It is basically a substance that bonds molecules to metal ions. I you have excess metals in your pool this can cause scaling and cloudy or murky water. You need something that will help clear up this problem and that’s were etidronic acid comes into play.
Etidronic acid can help inhibit staining due to its corrosion inhibiting properties. It prevents metal ions coming out of solutions and staining the sides of swimming pools.
Where do I find Etidronic Acid? You will never find this chemical on its own. It will always be in a pool cleaning product such as Arch Chemical HTC Metal Control. HTC Metal Control contains etidronic acid 20-30% and will definitely do the trick when it comes to removing calcium, iron, and other metals.
Looking for something a little less harsh? As the Pool Guy recommends giving FerriTabs a try. They are a safer alternative for treating metal removal in pools. 