Prazipro and gill flukes

So I'm in a nightmare situation at the moment. I have been dealing with what I believed to be gill flukes in two tanks right now, for the last 2 months. I literally cannot get rid of these things. I started by doing salt and methalyne blue dips, escalated to prazi, and it only seems to keep them at bay. My temperatures in my tanks go from about 75 to 80. My goldfish tank sits around 72 to 75. My betta in another tank (20 gallons) is refusing food and very lethargic. To top it off, I have to move 18 hours in three weeks, and I need my fish to be healthy in order to make the move.

So here's what I've done. Water tested everything, absolutely perfect parameters. I tried doing water changes a bit more often, I kept an eye out for the fish that were flashing against the sand and I dipped them in salt and methalyne blue. I've now medicated prazi pro for the last month or so, on and off. I increased aeration, but immediately after dosing, my goldfish will bottom sit and heavy breath, but pop back up a couple hours later. I followed the instructions on the packaging, 20 gallons per 190 MG. water change and redose after 5 days.

I found a koi forum that explained hatching rates of gill flukes in relation to temperature. They stated around 80 degrees could cause hatching in 1 to 2 days. So now I am trying a new course of action. I dosed the first dose in the tanks, waited 24 hours, and did another water change, and redose of medication. Then I will wait 48 hours, repeat. I'm hoping it will nuke the parasites, but I don't have high hopes. After this second dose, they are still flashing along the sand and itching. They accept food and are not very lethargic. I have a few other small tetras and endlers in with them, and none are showing signs of flukes. Only the catfish and the goldfish. Both graze through the sand. Are they getting re-infected through substrate??