I brought TDS up from about 200ppm to 500ppm using aquarium salt - half of what Hypancistrus used and it DESTROYED everything- my red foxtail turned black, watersprite, bacopa, baby tears, rotala Wallichii & a sword plant even frogbit were all turning brown all the way to the roots. It also did a lot of damage to my anubias nana and java fern. The only thing that couldn't care less was the drawrf hairgrass- it kept right on growing like mad..
Who knows why it works for one person and not for another? My pH at the time was ~6.4, temp at 78 and I raised the TDS to reduce stress on the fish during the nitrite spike when the tank was cycling. Maybe salt is okay at higher pH, but causes damage at lower Ph?