For those who don't know, the Stop is a solution where we bath the film negative after developing process, so it will stop the developing reaction faster making the develop time more precise and the image result more curate. And the Fixer is a bath to fix the image emulation on the negative by making it no more sensible to light.
After about 2 moths using the same Fixer mix I notice a black dust in it when I used for my latest negative developed. It couldn't come from no where outside the bottle because it is sealed to avoid contact to the air and to avoid evaporation. I was then intrigued because I have never seeing such thing during my 4 years working with my film negatives and prints in darkroom.
Later on, with the help of a couple of fellas, I learned my new storing technique was so efficient that I could use the mix much longer without it looses too much of it solution power. To the point where after a while, the negatives silver salt start to accumulate in the solution, becoming visible to the naked eye.
Worst than that, it also become visible on the following negatives it will bath. So the result I got from my last negative was surprising.
The cumulated silver salts made the image much more noise than expected, but I enjoyed the result because the noise was very aleatory on their position and size. To me it feels more rustic and artesian, I don't know why.
I still can filter the silver salts and keep using the same solution mix but I am serious thinking on develop more photographs as it is to obtain more nice aleatory noise on the image.