It's easier for you with prime because a capful of Prime treat 50 gallons,
You might want to read the link that I previously posted. 1 capful of Prime per 50 gallons is based on a very specific quantity of disinfectant residual, and without knowing what that quantity of chlorine/chloramine is in D. Wolf's tap water you can't possibly make a statement such as that. From Seachem's website:
Use 1 capful (5 mL) for each 200 L (50 gallons*) of new water. This removes approximately 1 mg/L ammonia, 4 mg/L chloramine, or 5 mg/L chlorine.
So how again is that easier for D. Wolf? You need a base number to start with, or it's nothing more than by guess or by golly, and potentially a huge waste of $$$. I've been attempting to get this message across to people for years,
you need to know how much chlorine/chloramine is in your tap water, before you can calculate how much water conditioner you should be treating with.
And last but not least, just so no one gets the wrong idea, you can indeed overdose with Prime.
I have seen tanks wiped out from an overdose or Prime, but they were extreme cases where very large quantities were spilled into the tank and the person felt that it wouldn't harm the fish. They were wrong. Both Prime & Safe are reducing agents, so when they run out of chlorine compounds (oxidising agents) to reduce, they will begin reducing oxygen in the water. Sometimes that can be just enough to tip the 02 scales in a heavily stocked tank with large fish, and cause serious osmoregulatory stress in ones fish, or worse, even death.