I'd actually agree with your one statement that once a tank is established there's not much you can do without adding a significant amount of biodiversity meaning entire rocks colonized with wild bacteria to increase biodiversity since the already present bacteria have such a strong foothold in the form of biofilms which offer a certain degree of protection from competing foreign bacteria.I'm a microbiologist - and a hobbyist. I have no problem with his 'methods' or products per se. Disagreeing with someone is not necessarily a personal attack. I would suggest (and many would disagree) that adding any bacterial product (except with an initial cycle) - is likely to have little effect in increasing diversity long-term - and I question whether increasing diversity alone should even be a goal?