Salt will only get out of your tank during water changes so if you dose it remember to add some back in during water changes and remember that water which evapourates doesn't count!
Salt has benificial effects, it helps to prevent infections and also it allows you to do water changes less frequently whether this is a benefit or bad management I don't know It increases the amount of nitrate, nitrite and ammonia you COULD have in the tank without the fish getting sick.
now i hear different tales about adding salt some peeps seem to swear by it others say it should'nt be used, i don't use it myself, perhaps it works for some but not others, do any of you peeps add it to your tank,
the african lakes used to be inland salt water lakes. they were fed from the ocean. when the lakes started to decrease in size the supply of water from the ocean was cut off. the salt started to disappear from the lakes and eventually became freshwater lakes. the fish were originally salt water fish that adapted to their changes in environment and evolved into freshwater fish.
salt is good to add to the tank. i do not use salt on a regular basis. i use salt when treating fish for disease or stress. under these conditions the fish's gill function is impaired. you may notice how fast and hard they breathe. when the fish is diseased or stressed this can cause the fish to go into osmotic shock. salt helps to aid in proper gill function and can prevent the fish from going into osmotic shock. salt cannot be used in scaleless fish though. can cause these tyopes of fish to get "burned" from the salt so to speak.
the formula for adding salt to the tank is one tablespoon for every five gallons of water. dissolve the proper dosage of salt in warm tank water and then add to the tank when completely dissolved. during water changes only add the correct amount of salt for the amount of water being taken out. if you have a 20 gallon do a 50% water change add onl;y enough salt for the 10 gallons you are replacing.
I have tried it as a tonic, but didn't notice any real improvement in the fish. Personally I'd rather use a medication like Melafix which is natural (tea tree oil based)
The only really noticable affect of using salt was the plants really suffered.