Originally Posted by mussum
isn't the point of adding salt to raise salinity? aquarium salt doesnt raise salinity? what does it do then?
i thought the problem with regular table salt was the lack of essentials minerals and added iodine...
Yes, adding aquarium salt to an aquarium increases salinity. So in a fresh water setup, constant addition of aquarium salt does nothing useful because a freshwater set up should not be salty. I know that sounds a bit silly, but "no salt" versus "salt" is the most literal difference between a "fresh water" and "salt water" set up.
Most freshwater aquariums use salt to treat illnesses like fin rot, mild bacterial infections, ect. Freshwater fish do not need any type of salt in their tanks 24/7/365. It actually makes them more resistant to aquarium salt treatments because they are used to a baseline level of salt and more salt than usual is needed to treat a problem. Also, most problems that are treated with aquarium salt can also be treated with really clean water and more frequent water changes. So I never rush into aquarium salt treatments if I can help it.
However, I still have my emergency stash of aquarium salt in case my fish gets something icky. But I very rarely have to use it for treatments. Illness treatments is the only good use for aquarium salt in a fresh water set up that I can think of.
To answer the original question, I have never thought of using table salt, khoser salt, himalayan salt, or any other salt besides aquarium salt in my tanks because most salts used by humans has an anti clumping agent. I can't think of what it's called at the moment, but the anti clumping agent is the reason why table salt can fall out of a shaker. Untreated salt will either be a mix of clumps and lose granuals or one sold brick of clumped salt. Aquarium salt is usually one big brick of clumped salt becaues the anti-clumping agent is bad for aquariums.