http://www.athiel.com/lib2/pguide/vitami1.html

I thought I had originally posted this but I guess I forgot! I would definitely double check your salinity as higher salinities make it easier for parasites to survive. I had a swing arm and my poor little bicolor got popeye. It was 9 points higher than it should have been.

Jim, might you have an article? I would love to read about it.

Running carbon is easy, what kind of filtration do you have? Most people use a filtersock and put some activated carbon in it, which can be found at any fish store.

Holy cow, after re-reading your first post, you are probably dealing with pop eye on your angel.

You are probably dealing with a salinity issue here, if I could make a speculative guess.

Take some water to a store and have them double check it.