What is the reason you are using salt? Is it for a fish illness like ick? If so, raise temp to about 83-84, but raise it slowly over a day or two. The only thing when adding salt, you should do frequent water changes to get the salt out afterwoods. Change about 25 percent every 2 days.
As far as nutirents, you will need some Flourish or TMG (Tropical Master Grow), and iron is another nutrient that plants need. You will start to learn this by browsing the forum.