dips should be 5 mins unless she is showing sings of stress you have to make sure the temp is the same as the tank water and the ph is the same or she will get stressed fast. I have done dips as long as 15 mins. You will have to get some garlic extreme and selcon or even garlic guard and zoecon will work or a combination of these. I do feed my fish garlic and selcon on a regular basis at least one shoot of booth in flakes with 5ml tank water soak for 5 mins and then add extra water and feed to fish. I also feed at least one other time in a week just garlic soaked flakes same way. The selcon is amino acids that fish need to stay healthy and the garlic boosts their immune system. The temp is going to fluctuate a bit that is how heaters work unfortunately. the SG should be around 1.016 to 1.020 I would start at 1.020 this allows the fishes body to not have to work so hard to keep hydrated. Hyper-salinity is at about 1.010 when returning fish to regular salinity you will have to raise the salinity slowly do it over a week so raising it by 0.002 per day maybe a bit more when you get closer to your 1.025 will be OK.
Sorry I didn't get back to you sooner I have to spend time with my wife and kids , too.

I help others that are new to the hobby because I didn't have hep when I started some 20+ years ago. I would get her into the QT as soon as you can and get some thing to help her heal. You could try Melifix If you know for sure that she does not have anything else wrong with her except the fin and eye. I would wager there could be an infection and that is why she is so faded. That is why I suggest a broad spectrum anti-biotic this should help with infection and if she has any parasites. I know melifix works for pop eye I have used it a couple times but do the anti-biotic first and then you could use melifix.
Do not use them at the same time as one may counter act the other. here is an example in old age home they can not serve grape fruit juice as it counter acts with quite a few medications the people use.

Bill