I recently moved and the water is hard, but not like where i was, so I’m trying to learn about adding salt.
Is it really beneficial?
How much do you add?
Does it have to be aquarium salt like API’s or would something like Instant Ocean work?
Can you provide test data, comparing water now, to water before?
Is the change in hardness due to general hardness, or carbonate hardness? and as Milingu asked, (more importantly to some species) is pH actually different?
The difference may be minor as far as the fish are concerned, and "not" warrant any chasing of parameters.
such as, If your KH is similar but the GH is lower, and if so, and you want to be persnickety, experimenting with a tbsp of Epsom salts from the pharmacy might be sufficient.
If it's the KH. a tbsp or 2 of baking soda could be added when doing a water changes.
Is your Alkalinity now different? This may mean it could just take more water changes to result in the same buffering capacity.
Is this a private well, or water from a public water supplier?
If from a public supplier you may be able to download, or request the EPA yearly drinking water quality report, to compare data.
I used to generate and submit that report as a chemist/microbiologist at the public water supplier where I worked, and it was easily accessible to "everyone" on line on the cities website, by entering the cities name (and .gov), followed by EPA drinking water quality report (usually separated by the year)