Some of the products have both types of bacteria. Just wondering since you see a huge reduction right away, what is happening to the stuff you currently have / can normally cultivate? Is it being outcompeted for nutrients? it seems the stronger stuff has either a shorter life span or can not reproduce as you continually have to dose to keep up with the results. I've had a mini cycle after quitting microbacter 7. I weaned my system off pdb so no issue that I can remember. I just wonder about these things sometimes. I have a lot of info and a lot of people I know are in the "field" of biology of one sort or another. Trees, reptiles, common house hold pets, farm animals, water treatment, wet land conservation (birds) no fish though. They have all given me their two cents worth but some info contradicts....anyway it will be interesting to see what systems are being built and what ones work better and to discuss why we think that is.