Kevbshields, I wouldn't count on salt to affect callamanus worms. They are insanely tough critters. Can be paralyzed completely by multiple dewormers, yet remain in the host and recover. Only a heavy dose of Levamisole works.
Without hosts, you've hopefully managed to eliminate them. But as you say, it only takes one bad apple in the future, and callamanus can exist and kill without any external indication - I lost many guppies for three months before spotting the first worm, and I had two sets of eyes actively looking for them. I recommend adding Levamisole treatment to your quarantine procedures. You'll find it most easily by searching for "Vermisol powder", used for avians. Keep it in the fridge for longest shelf life. Two potential sources for you: