You need not worry about a magenta tinge to your negatives.

And like as not, the commercial labs probably use something similar to D-76 in a replenishment regime. What they do do though (if they are any good) is control the chemistry carefully, including things like ph, and wash quite thoroughly. They probably use treated water as well.

I never have problems with pink/magenta negatives, but I'm blessed with excellent tap water, I do pre-soak, I use replenished HC-110, I use stop bath, I use two stage rapid fixer, I use hypo clearing agent and I use a ten minute running water wash.

I list these things not because any particular one is a solution, but rather to point out that there are all sorts of variables that can influence the result.