Hi Vinny,
The sodium chlorite solution in the MMS bottle is highly alkaline (and can give you an alkaline burn if you use it on skin undiluted). But when mixed with the citric acid solution (or vinegar or lemon juice) at a ratio of 1 drop to 5, it is brought back to a more neutral ph.
The chlorine dioxide produced when the solution is made kills bugs by oxidising them, literally ripping electrons off the acidic molecules which destroys them in seconds. It doesn't work by being alkaline, because once mixed with the lemon juice/vinegar/citric acid solution, it isn't alkaline, it's near neutral ph, maybe even a bit acidic if you use a lot of the acid activator.
Maybe sticking a ph test stick in it would be a quick way to find out, and I'm sure Jim Humble covered this topic somewhere in his book far more accurately that I am here.
Anyhow, I haven't tracked my ph whilst using it, so I can't say for sure on this subject, but I do know that once the solution is mixed correctly, it is no longer an alkaline substance.
HTH, ruth