Question about Prazi?

I have three fancy goldfish that will be going into their new 55 tomorrow. I have had them for a week and they eat well, have normal poop, swim well and show no signs of parasites. But I know that looks can be deceiving. So I will be treating them with "Prazi"quantel or Parasite Clear Tank buddies. I will be getting the 8 pack that treats 80 gallons of water, or 10 gallons per tab.

These are admittedly the first fish I have gotten from a pet store in...about 15 years. All of my current fish are from very reputable breeders so I haven't worried about preventative treatments for them.

The tank they will be going into does not have any existing fish but I don't want to cross contaminate my other tanks with my python. I hope to get them into their new home as soon as possible.

So...How many times should I treat them? Would one time be enough?