Bobbo wrote:
I have seen the growth in my tank. YMMV. (It was gone after the bleach treatment.)
I'm curious, how did you see inside your tank?
Generally most life forms(bacteria included) need energy and nutrients to actively reproduce. There may be warmth but without sunlight and some type of sugar or amino acid, growth will be really limited. Your nose does a good job letting you detect excretions from bacteria( ie sulphur ). You may not like the "plastic taste" after water sits in there a while but that will not cause illness.