Water conditioner disaster.

[Congoman]

For the record, I'm not "putting too much thought into this;" I merely wanted some help with the mathematics of it...

Here's the response I got direct from Seachem regarding this:

Thank you for using Prime. It is perfectly acceptable to dose Prime directly to your tank, but you will use less product if you dose only your replacement water. If you dose Prime to your tank directly, then you should dose 6mL of Prime. If you only dose your replacement water, then you only need to add enough Prime for the volume of water being changed (roughly 2 drops of Prime per gallon of water). Either way is acceptable.

So, it seems, either way is indeed okay, just for everyone's information; apparently, dosing the tank before new water goes in won't be harmful either...

I do believe I posted earlier that if dosing your tank directly has always worked then I wouldn't change. I was just trying to save you some product.