You treated the tank a couple times, so there are things to consider now. That not only interrupts some of the ick, it also interrupts the bacterias and symbiotic microbial life in your tank and creatures like the BTA. There were numerous symbiotic bacteria and algae in the anemone. The bacteria in your tank can be reseeded with some kind of culture and then not use medications again. NH3,NO2,NO3 should all be 0 (and can be if you have a good bacteria population) and phosphate <0.5. If your kit is only capable of <5 reading, then it sounds like someone sold you the wrong kind of kit for a reef tank. Providing the water is good (RO/DI used for top offs, etc) the anemone can recover its symbiotic life. It can take some time though and there will have to be plenty of blue light for it in the meantime. Other things such as flatworm exit, joes juice, aerosols used in the home, cigarette smoke, paint fumes, a fireplace (puts out carbon monoxide), etc. can also affect the symbiotic life in the anemone and can lead to its demise. Good luck, I hope its only one of those cyclic things its going thru and it recovers.

There is never really enough information in one of these messages to really solve the problem. Not knowing what you or anyone reading this uses, this may bear commenting: Using tap water for top offs will eventually lead to the concentration of the pollutants in our water because they don't evaporate from the tank. Those include some heavy metals that are deadly to reef life such as copper. In tap water its below the acceptable level and therefore safe for drinking water, but, it is one of the pollutants in our aquifer water. Some of the pollutants are absorbed and detoxified. For a while. Sooner or later they saturate the cycle and make it into an area of the tank substrate where the pH is low and then are returned to the water column or they hit a kalc drip and are freed in the high pH area to act again on whatever is in the tank. RO/Di (for top offs and mixing) and good brands of salt mix are the only safe way to go.