Ok, so everyone has a slightly different way of doing this but this is the method I have given to multiple customers over the years and always received great news back. It has worked for me personally as well, which is why I recommend it. Again, its not a hard and fast rule, but is a method that has worked well for me. You'll want to get the tank up to about 86 ish degrees, but slowly and you'll want a total concentration of about 1 tblsp/5 gallons which you already have so that will make it a bit easier. You'll want to do regular scheduled water changes and it will take about two weeks to get it completely gone.
Important things to note with this method: heat increases the life cycle of ich. This means in the first couple of days you will see a lot more spots, but don't let it panic you. Those parasites are on the way to end of their life. Salt inhibits the ability of the eggs to hatch, so it's important that you keep the concentration slightly higher than normal.
(I'm assuming you have a 55 as that is what I think I remember it was)
Today (29 July):
-Raise temperature to 75
Thurs (30 July)
-Raise temperature to 78
Fri (31 July)
-Change 15 gallons
-Raise temperature to 80
-Add 3 tbs salt
Sat (1 Aug)
-Raise temperature to 82
Sun (2 Aug)
-Raise temperature to 84
Mon (3 Aug)
-Raise temp to 86
-Change 15 gallons
-Add 3 tbs
Wed (5 Aug)
-Change 15 gallons
-Add 3 tbs
Sat (8 Aug)
- Change 15 gallons
-Add 3 tbs
Tues (11 Aug)
- Change 15 gallons
-Add 3 tbs
Stick to the water change schedule.
At this point you should have it all gone and can start lowering your temperature back down again. Slowly. Additionally, that amount of salt content is a little high for what I would normally say is safe. A lot of fish species really don't do well with that much salt in the water. A tbs for every 10 gallons is generally more what is used. Personally, I only use salt when I get new fish or when treating ich. Even then I kind of stopped using salt for new fish and just went with stress coat instead. However, if I remember right you have mollies and they do like the salt in the water as well as higher temps. I'd let the tank stay around 80 for them if I were you. You'll have less ich problems in the future if they are in higher temps where they are less stressed.