As a independent LFS owner you unfortunately cannot compete with BRS and other online "big box" type retailers.. As a small business owner myself I have went through the efforts to get a dealership with different company's only to find I could still buy their products cheaper on
amazon than I can through them with my "dealer" pricing.. This is what make things really hard on us small business owners.. Customers come to us for advise, experience, and warranty.. then buy from BRS or
amazon cause they can sell it cheaper than we can buy it. Not much is worse than making a nice sale to a customer, only to have them bring it back the next day and tell you how much cheaper they can get it on
amazon and they need their money back..
I would not pour much money into the high end items.. not at first anyways....
I also have concerns about the QT idea.. While Qt is very popular on this and other Internet forums.. In my experience only a small percentage of people in any particular hobby use Internet forums.. In fact every person in my area I have found that has a reef system does not participate on this or any other forum.. and not a single one of them uses QT.. I would question what the actual percentage of people would use the service you poured so much of your precious start up money into setting up... I like the idea myself, just not sure of the profit potential. And face it if there is no profit you can't do it.. If you do try it I would definitely start small and grow it as the demand grows..
I do really like the idea of a "coffee bar" type area.. maybe a soda machine as well.. huge profit in coffee and sodas.. and it encourages traffic and people staying, plus adds a revenue stream.. Try and create a area where people feel comfortable just hanging out, are out of the way of employees and other customers but are still in sight of point of sale (Point of sale) signage and product. Lingering customers equal sales... As well as creating a area for club meetings..
Find a dry goods product no one else offers in your area, maybe even try and get a exclusive offering from one of your suppliers.. keep a accurate inventory, and return, discount, discard, products that are not selling and replace them with something else.. livestock to. Shelf space/tank space is limited only use it for product that moves quickly.. This also goes against what some people want to see. i.e. rare and hard to get items.. the problem with these is they also equal expensive and slow moving.
Sorry if this is not exactly what you were looking for with your OP just thought I'd give my opinions as a fellow sbo... Good luck whatever you decide...