Hi, this is my first time doing this, I made an all grain Sierra Nevada pale ale clone, the beer has been fermenting for 15 days in the primary the Krausen has fallen( I think) but there are some bubbles floating in the carboy. I'm uploading some pictures ( the ones that the beer appear darker is because of the flash). Is has little bubbles it does not seem to have any mold I opened quickly and the only thing I smelled was carbon dioxide (like when you open a container after dough has been rising in it). Can someone please tell me if it seems like it's infected. Thanks.