okay so that bag says its triple cleaned, but nothing about buffering/cal-mag charging
this is what you do before planting (if untreated coco you would soak in around 3x water volume to coco in 5.0 ph for 3 days if not pre-rinsed . after the ph stops changing you swap then follow charging steps)
-submerge coco in water, add 1/4 recommended dosage of cal-mag
-ph down it to 5.4, wait a day
-check ph, if it rises , lower it, this means you have to "buffer" the coco
-get it to stabilize at 5.8 in the cal-mag water
-drain and squeeze out the coco, it is ready for planting
-I also charge the coco with 1/4-1/8 dose nutrient feed instead of using nutrients in the beginning ( just so i know there's something there, i know tap water has nutes)
but yeah if you were worried about excess salts in the res because of stagnant water i would just rinse it good how i said or whatever, doesn't have to be R/O in fact that may shock/disturb any beneficials that would be taking care of any stagnant issues. if used straight so if i were you id do it with tap water if you use that or r/o water with 1/8-1/4 nutrient dose
if all else fails there's the root rot cure
smell it, if it smells yucky, it is yucky. it may help to saturate it a little if very dry
also wanted to point out see how it says "inland india"?
this means there are less salts on the coco, because for the most part, coco is growing next to the ocean and thus the high salinity.
that stuff seems legit, next time i'd definately go perlite reservoir or do some aero-clone transplants to reduce the chance of rot in the res