Diving grade is manufactured and tested to a much higher standard, we would not advise anybody to dive on medical grade, it could be a life limiting decision. We and other manufacturers supply diving grade with indicators if you really want them. Indicators became an issue when one manufacturer (not MPL) changed the type of dye that the used which reacted more and gave the scrubber media a bad chemical taste. I believe thay have now stopped this. Does anyone know if indicators still cause changes in taste and if si with what products?