If I had specified a year running uv I didn't intend to imply it had to be ran a year...was intending to say after the tank is guided correctly it won't come back, we'd see this more often in aged tanks vs always new ones the threads show.
In my tank rework threads, we run uv just long enough to gain control they aren't permanent where we used them for various cures for pelagic invaders. Mostly we're dosing peroxide, but I collected a few good UV runs not any different than one can search for if we Google up the times people cured things with uv. If op doesn't want to run uv or try peroxide and is willing to lose the investment beforehand, not a prob. Only mentioning options to try before throwing towel, options not tried for six months readily available...especially the peroxide run.
The uv can be removed once an obligate hitchhiker is removed if it was powerful enough during the run time, since most of these mystery invaders rely on hitchhiking to get vectored into a tank. My point was there is a finite time one would have to run it since white clouding invaders aren't typically a mainstay in reefing.
I haven't owned this brand of rock, but being a thread watcher and memorizer I've seen more than one instance of these growths on these rocks...I'm sure key word searching would turn them up over the last year or so.
If someone is using grossly oversized uv, rare for reefing as people are used to buying the one sized for their gallonage, you can get better return on time investment than if you are using one barely sized/flow matched to the tank. I used only pond sterilizers when I had a large tank, oversized, to cheat out various algae and cyano. As far as to why multiple users of this rock are reporting bac or seemingly bac invasions, don't know. Part of the mystery, run a search on Walt smith + bac invasions to see
I googled: Walt smith live rock bacteria bloom got lots of these
http://www.reefcentral.com/forums/showthread.php?t=2528402
Perhaps they are farmed from a region where those bac are residents and when combined with any dieoff or organics within the rock or carbon dosing by the keeper they come about? Musing based on thread puzzle pieces, not certain. The takeaway for this thread is that more options are available, if it's cheaper to throw out the rock and not try them that's not a problem.
People that have to run uv long term to suppress growths are typically not using oversized uv, they are just getting by and the results show that. In my giant nano reef.com peroxide thread we took a nano reef of roughly 30 gallons with persistent dinos and fried them back by using 55 watts on the nano/UV
If searching for correct sizing/wattage for 30 gallons the going recommend is approx 9 watts or less depending on model