Flatworm Exit not working

[J.Lloy]

I had done 3 treatments to my tank. I used full bottle for each dose (230 gal plus sump) first time i had so many dead worms I was worried and did water change right away and ran carbon. Killed most, second dose left a little longer still had lots of dead worm floating. That left me with just a few visible worms so did a third treatment and left for a few hours then just started to run carbon, can't remember haw soon after I did a water change. After that I got two yellow coris wrasse for the display. That was back in the fall. I now have worms again in my sump but have not found a single one in display. Just have to take care of the ones left in the sump now.