Thank you Loris, I am grateful for your help and guidance in the matter.
I noticed that I haven't mentioned how long SA mixed in water will keep its strong acidic properties, it has been a few weeks there is no problem yet (It is still around Ph 1, and treated approx. 10 full sheets with it). But in powder form it would keep indefinitely in normal humidity and temperature. It is quite cheap so, I do not consider aqueous solution's shelf life to be an issue.