Can not you wear some kind of protective long-sleeve gloves to take out those samples. Of course every chemical will affect skin. More time you dip, more effect will be.

Thank you Subhash C. Juneja sir for reply. In my laboratory tank height is more than 2.5 ft, therefore for the proper placing of the specimen, I have to go inside the tank.

For a RG discussion on the pH of pure sodium sulfate (Na2SO4) aq. sol.:  https://www.researchgate.net/post/What_do_you_call_the_electrolyte_of_sodium_sulfate_a_base_an_acid_or_neutral