Well my fish seem to be doing ok, apparently the system includes water outside. I would literally need to run to a neighbors to get unsoftened water, which i want to avoid since running back and forth once a week with a bucket is gonna be troublesome for them and me.
I use morton's solar salts for the system and according to their FAQs, its ok for ponds and freshwater as they have no additives but they recommend only to use fish that want soft water, obviously. I have tetras, otos and snails. The snails are not doing well, their shells are clearly very thin and the back ends of the MTS shells are all dissolved, so instead of beautiful cone shaped snails i get stumpy shelled snails. Other than that the MTS still breed actively and i know i have hundreds in my substrate.
One things I am worried about is what would happen if I just added calcium like crushed coral or seashells, would the salt in the water react and create that brown sediment i see in my softening system? Also, how do i re-add magnesium to the water?