I have had them in the past and just noticed that they have returned to me recently.

In my experience, flatworm exit works very well as long as you follow the directions carefully. I usually have bumped the dosage but that's my only change.

I did make up a small siphone pipe with 1/4" line and then a small piece of ridged pipe at the end that lets me siphone up the little critters as much as I can while not draining too much water as it takes a long time to get them. Once I've done that, I treat with Flatwork Exit (FWE) and then get ready to siphon the ones that float free before they fully die and release their toxin. During the treatment you should have no charcoal running but once they really start to die and you are sucking them up, turning the charcoal back on (ie a reactor) is a good idea to help clean the water. Also make sure you have good aeration in the water when you use FWE.