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PBW out of solution will last for a year and maybe even longer. In solution we say it's at its best the first 24hours, after that the oxygenation will start to leave the product. You could still use it up to about 24-48 hours after being in solution but it has lost about 50% of the effectiveness. Hot water is best when using it, between 100- 160 is the normal temps to use
it at, but can be used at a lower temp as well. We always look at Time, Temp and concentration. How much time do you have, what temp can you run it at and what concentration are you using. We recommend 120-160 degrees, 1/2 to 1oz per gallon, for about 30 min. You can adjust as needed. Please let me know if you have any other questions we can help with.
Five Star Chemicals & Supply Inc.