this may sound odd but i thought it was not a big deal until it kept happening time after time after time. it appears that in some boxes of grout there's some type of red dye in them. i mix the grout and while spreading it i get an occasionaly red streak. it's not a big deal and it always cleans up easily but my question is, why is it there? my only guess was that it's put into the grout and meant to disolve in the mixing process and it was some strange way to let you know that the mix was wet enough. but if i use a dry mix or a wet mix, i get the same thing all the time. i'd say i get this red stuff in about every other box of grout i use and i probably use about 30-40 boxes per year.