co2 booster bucket

I cant seem to find and solid reviews for these things. has anyone used one or know first hand of anyone who has used one? i was told by the rep from the company that it will maintain 3000ppm for up to 90 days. but i find that hard to believe nor why anyone would want it that high ever! i plan on trying one in a 55"x55"x84" tent with a fuzzy logic co2 monitor system. would love to get some info before i buy the damn thing. please save the theories on what you think it will do, ive seen enough of those. i only want response from people who have actually seen them.