First off stop using bleach. Use Iodophor or Star-San. Less chance of band-air taste and they are no rinse. Keep a bucket near you for the spoon and thermometer. Secondly, the munich and maybe even the special roast must be mashed. Not sure a 30 minute steep did the trick. In addition, yeast do not kill bacteria. The bacteria is always there. If you pitch healthy and abundant yeast they will get going and overpower the bacteria before the bad stuff has a chance.