Some sanitisers, like star-san, chemipro oxi and betadine are no-rinse in certain dilutions. Star-san can additionaly be kept diluted in a bottle for months and used whenever one wishes. Can the same be done with the other two?
Well, Chemipro Oxi I would not consider a sanitizer...cleaner, sure, but it is essentially sodium percarbonate - it technically CAN be used to sanitize, but the amount needed makes it pretty uneconomical.
Betadine, on the other hand, can be used for years...bottles may have an expiration date (typically required on medical-type solutions), but it can be ignored. The rules for use would be the same as StarSan, which is:
Diluted StarSan or Betadine cannot be used indefinitely - it depends on the pH of the solution. For effective sanitizing, you want the pH to be below 5. Homebrew and aquarium stores sell disposable pH test strips, or you can buy a pH meter.
I usually just refill my spray bottle of sanitizer whenever I make up a new batch. If it has been awhile, I test the pH or just make up a fresh bottle. Better safe than sorry.
Chemipro Oxi can be used as a sanitiser, however it is not listed as one (as far as I have heard) because in Belgium you have to pay special taxes for sanitisers, while cleaners don't have that problem. I contacted brouwland for the above matter, and their response was the following:
I think this, along with Jim's post, concludes it all.