I am wanting to know how much Seachem "Prime" I should use to help detoxify my nitrites? I had gotten rid of my ammonia issue about a week ago. I slightly have some nitrates and have slightly more nitrites. Ive been doing water changes once a week to help. Should a add a capful of Prime maybe every 48 hours or so directly? And then also of course at my water changes? I have a 55 gallon aquarium with only 7 small fish in it.