I use the whole Aqua vitro regime is pricey but man it works great.
If you have allot of coral use a half dose at first for a few months then go to full dose of fuel otherwise you might get some algae. If you don't have much for coral start a quarter dose and only use half after a few months. The few months gives some time for your bio filter to adjust to the increased load of nutrients so you don't get algae issues.
It needs to be refrigerated once opened unless you have a very very cool basement if it ever goes really bad smelling and a dark brown it has gone bad and don't use it. It should have a slight smell and a orange/gold tinge but when it goes bad it smells like a dead fish and turns brown. I had that happen once in the summer and isn't pleasant lol.
After a few months corals seem to be better coloured with better pe and slight increase in growth.
If I remember right a capful does 25 gal but would have to check, it should say on the bottle recommended dose (1capful is 10 ml)