Yes, leave the main fallow for 6-8 weeks at least. The UV
will make no difference really. Be sure you keep the main tank fed every few days or so to maintain the biofilter.
The fish not having spots anymore is just a phase of the parasites lifecycle. The trophonts have simpley detached to the tomont stage where they can multiply and start the process over again. Only once the salinity has been dropped to 16 ppt
or lower (I recommend 14 ppt
) will you see possitive long term results. Hyposalinity attacks the tomont stage of the parasite, not much esle so be sure you keep the fish at the hypo level of treatment for a full 4 weeks after the last trophont is seen
on the fish.
Make sure pH and salinity are checked twice daily and the nitrogens are checked at least daily. Do water changes as needed to control higher numbers and if available, use polyfilters to help "scrub" the water of harmful ammonia. It's not uncommon to have to buffer the pH throughout the process but especially during the drop in salinity. Using pH buffered RO
water for the initial salinity drop will minimize that.