I am a pretty novice brewer but have brewed a few times before. This time I was brewing an extract IPA and was topping off the fermenter with spring water. I didn't have enough to top off to 5 gallons so I used a half gallon from an old spring water bottle that had been opened for a while. It's now fermenting but the krausen is greenish brown not that foamy white I'd seen in previous batches. It had a lot of late addition/ flame out hops so is it just those particles or should I worry about it being infected?

