Flat worms, best practice.
 

So I have discovered flat worms in my refuge area of my sump. I will be pulling everything out of it, and giving it a flat worm treatment.

However no signs of it in the rest of the tank or the other sections of the tank. Should I dose the rest of the tank for good measure ?

Since they are as toxic as fukashima why not isolate the sump and treat it and then treat dt after.

I'd go ahead and assume they are everywhere. Use a full dose of flatworm exit and have GAC and a big water change ready. You can also try the shield head slug and wrasse route but nothing is a guarantee.

Ended up dosing all affected macros in a 5 gallon pail, and isolating the refuge.

Completely drained the refuge, and scrubbed the walls with a vinegar bath. Added new salt water, replaced macros and added an ato the isolated refuge, will be leaving it offline for quite awhile.

Dosed the tank, just to be sure, then performed a 20 gallon water change after. Hopefully that should be the end of that story.

Thanks everyone