Prime is a reducer too. Seachem even advise not to dose both prime and excel on the same day. Found it on their faq section last week.
Not a lot of people know that!😉
Seriously i have had instances where I've dosed liquid carbon and the fish reacted to it.
The usual fish up at the surface plus rapid gill movement etc
I mentioned this before in some other post....so need to ensure that there is ample O2 in the set-up.
I don't think it would be much of a problem if you have low stocking levels...although i maybe wrong.
Regarding Prime...that's interesting hobbyists, have had problems with Prime dosing.
Cheers
hoggie