I recently had to adjust the amount of cleanings I did on my tanks. My small tank I was instructed to keep the water "clean enough to drink....not that you'd want to". My betta is dealing with fin rot; even with medications it's really tough to clear and I've lost a few to it, so now, I do a BIG water change every couple of days.
However, if you're adding salt, do not add any more salt until you remove water!! Then, add only enough to add up to the original amount; ie, if you originally put in 2 tbs, then you remove half the water, and replace it, then you would ONLY add 1 tbs, to end up with the correct amount
. If that's what you are going with, that is (salt).
The changes can only help your beautiful fish. I'm not a fan of fancy goldfish at all, but yours is truly remarkable. Silver! She's a beauty
Give her that fresh clean water that she deserves, and if you can, remove the tank mates.
Too much stress on the system of that size, since the poop factor with goldfish is off the charts....good luck!!!