Thoughts on salt treating planted tank?

[Superjoepez]

I have a group of 4 Corydora Aneus and 3 Balloon Mollys along with a group of 7 Molly fry in a breeder box in a 29 gallon planted tank. One of my Balloon Mollys keeps getting infections. At first I thought it was Ich and treated for that twice with Ich-X. Then treated for Columnaris once with Marycin. This was all in the 29 gallon. When the Columnaris came back again it also came with a swim bladder issue and thats when I finally got a 10 gallon hospital tank. I moved her and the other female to that tank and did a back to back treatment of Marycin while fasting. Thought she was good and then a few days back in the display tank a new infection popes up, this time its fin rot and something that looks like columnaris by her eye. She is now back in the hospital tank with a 2 tbsp per gallon does if salt. 
 

My question is would it be helpful to add salt to the display tank? Could she be getting sick again and again from the tank or is more likely she is stressed in that tank?
 

If it IS a good idea to salt treat the planted display tank what doesage should i do not to kill the plants? The plants I have are Java Fern, Anubias Nana Petit, Dwarf Aquarium lily, Tiger lotus bulb, Moneywort, Bucephelandra, and some Red Root Floaters.

Im just really trying to get this girl healthy. 
 

Thanks!

[Superjoepez]

8 minutes ago, Superjoepez said:

I have a group of 4 Corydora Aneus and 3 Balloon Mollys along with a group of 7 Molly fry in a breeder box in a 29 gallon planted tank. One of my Balloon Mollys keeps getting infections. At first I thought it was Ich and treated for that twice with Ich-X. Then treated for Columnaris once with Marycin. This was all in the 29 gallon. When the Columnaris came back again it also came with a swim bladder issue and thats when I finally got a 10 gallon hospital tank. I moved her and the other female to that tank and did a back to back treatment of Marycin while fasting. Thought she was good and then a few days back in the display tank a new infection popes up, this time its fin rot and something that looks like columnaris by her eye. She is now back in the hospital tank with a 2 tbsp per gallon does if salt. 
 

My question is would it be helpful to add salt to the display tank? Could she be getting sick again and again from the tank or is more likely she is stressed in that tank?
 

If it IS a good idea to salt treat the planted display tank what doesage should i do not to kill the plants? The plants I have are Java Fern, Anubias Nana Petit, Dwarf Aquarium lily, Tiger lotus bulb, Moneywort, Bucephelandra, and some Red Root Floaters.

Im just really trying to get this girl healthy. 
 

Thanks!

Forgot to mention, I have pretty regular water parameters. Nitrates stay between 20 and 40 ppm, temp at 76, ph right at 7 to 7.1 and gh around 100 and kh at 80.