Tonight I listened to an interview of Charley Talley, creator of StarSan, and it's not clear to me that this is correct. He says in the interview that the killing power of StarSan comes from the combination of the acidic aspect and the anionic soaping aspect (he had a different name for the soaping aspect--detergent, surfactant?--I can't remember). He specifically says that either alone is inadequate, and if I heard him correctly, he says that what's degraded by hard water is the ionic soaping aspects. He said that using distilled water, which lacks the minerals that degrade the anionic properties, would result in a very long-lasting solution, corroborating ChaosStout. Me, I don't know, but if I heard him correctly, it is not the case that you can assume effectiveness of a low pH StarSan solution.
