too much pool?

Last summer was a good summer. we alternated camps : with and without swimming to avoid A catching a cold and having it linger. This summer I was not as careful, A swims all the time (we had a good winter too) and now he has this tiny bit of cough lingering and I never know if it is going away or trying to get back. Maybe it is not swimming but the remnants of a cold. Do not know so I do double dose of flovent but need to stop soon. Perhaps just a bit of xopenex instead?
I hope he will get back to a good healthy baseline soon.
And we are trying to inroduce fish oil supplements (carlson) but he dislikes the "fishy" (after)taste.
tried thyme tea - another invention.