ACV and other questions..

[hugz4all4]

So Im back.. with more question regarding my dogs runny eyes. I tried the apple cider vinegar agian, started about 2 weeks ago, I am using less, dogs are drinking the water etc. I know its probably too early to tell whether or not its working for thier runny eyes but I have noticed that thier urine is dark almost red, instead of the normal light yellow and it has a very strong odor, in the summer while I was trying the acv they killed my grass in numerous spots with thier urine.(however I was told i was using to much) I at that time didnt notice the color because it was on the ground, now that we have a ton of snow its very noticable. This started about 3 days ago. I have stopped the ACV, because I am concerned..for those who use this product.. is this normal??
Next question.. If the runny eyes are from foods, How long will I know whether or not its still the food??? I have them on grain free.. they eat a few teaspoons of EVO venison wet in the a.m and have access to Acana wild prairie all day. Theyve been on both foods about a month. They get a few teaspoons of yogurt with angel eyes mixed in (less than what is recommened on the bottle and not everyday) for thier evening snack. The red staining is less but still happening. I wash their faces everyday with plain water. They no longer have the staining on their feet, mouths or butts so that's a plus, but thier freshly groomed faces look a mess. .
If anyone has any advice/info for me it would be greatly appreciated..
TIA..

forgot to add that they also get a few drops of Ark naturals royal coat express a couple of times a week..