I don't want anyone to hurt their tangs or coral so take this for what it is. I have treated several large acro dominant tanks over the last 5 years for AEFW with tropic marin elimiphos rapid- which is the Lanthanum Chloride. I treat at 5 mls per 100 gallons of water, dripped directly into the display tank in high flow area. The objective is to build a concentration of the La in the tank where the AEFW are. I do this twice a week for about 3 months. Effective skimming is critically important but I do not change type or frequency of the physical filtering (socks, floss, pads) in any way. My belief based on observation is that the large adults are hurt by this but the smaller ones are killed. No effect on the eggs so you need to go for the three or four months to make sure all eggs hatched and all babies are dead. Let the adults die off thru stress of the treatment and old age. You can monitor the impact of just this change by basting the corals directly in tank and watching for large adults to come off the coral. You will see less and less and then eventually you will go for weeks and see none of them anymore. You cannot stop treatment for at least 2 months after the last one is seen just to be sure. Baster at least twice a week to watch for changes.
I watch ULR P test Hanna and make sure to feed heavy enough to keep above 10 ppb. I feed acros a mix of equal parts benereef,reef roids, dried cyclops, and spirulina. I test P ppb the day after treatment. Watch normal parameters and adjust as needed to prevent any swings because growth will restart and consumption will increase as the little pricks die off.
I know I have not posted much and don't have the history on the site but this has worked very well for me and has been safe as far as I can tell for all fish including yellow and PB tangs.