Yes mine came back and I have not added any additives since. I try to change the current every once an a while, and I do water changes about once a week 10+%, as I have a 10 gallon nano that i'm converting to NPS tank. I think the Coralvite is fine, I would just not add what the bottle says.
One think what have you been feeding them? I found that I was able to get all of the to come out with Cyclopeeze, and then give them a bit of mysis. Do you spot feed or broadcast feed?