Yea on the UV subject, I am not sure how much it helps but so far, does no harm. I did got hit with dino and the UV did suppress the outbreak but did not help eliminate (I think mine is the ones that stayed on the surface).
Like you said, bottomless pit..haha. I might introduce another fish and that's about it...focus my time on corals.
Update on a video just taken on the new setup - 12G Display Tank (DT) and 12G “Sump” Tank.
Although my KH is kind of low at 5.4, so far the Zoas are doing ok. I am looking at to raise the KH level and hope that will not affect the Zoas.