Eyes tear staining again

Q: I have a white Pomeranian (6lb), she is 2 years old and she has started to have tear stain (like 8-10 months ago). She is always taken angel eyes soft treats and it worked for her before. Until we traveled to spend a month and I forgot to take the angel eyes with us... (she had traveled there before, so it was a familiar place) when we came back from the trip her eyes started staining even though we started giving her the angel eyes again. I clean it all the time and it still hasn’t gotten any better. I read that it helps to change her water to distilled water so I plan on doing that (does it really help?). She has always eaten the Royal Canine (Royal Canin Size Health Nutrition X-Small Adult Dry Dog Food, from Amazon) so I am not sure if it could be her food too, since I read she may be allergic to it(?). Another thing that I read that may help is keeping the area dry by using a little corn starch, should I try that too? So I guess my question is, which would be the best food to gave her to avoid staining, and does distilled water help? Is it a good idea to put a little corn starch on the area to keep it dry?

A: If there is a lapse in treatment with an oral product once you start back it can take 4-6 weeks to see the benefit. Those products do not remove the stain they try to stop additional staining so the previously stained hair has to grow off. I do not feel the food is part of her problem. Purified water is always a good choice. I don’t feel the corn starch will help.