Hello, my fish-mates

,
You may recall I had an issue with some goldies a month or 2 ago. Well, whatever 'it' was (that manifested a pale, fluffy swelling on fins and torso), it is back with a vengeance

. One of the two fish I treated last time has a sizeable outbreak on his crown and some spots on his tail fin. The other, a pink goldfish, has similar marks but not so bad, on his tail fins.
I've isolated them in a heated, 50 litre holding tank

and thrown in some general anti-fungul treatment, a little salt, and 4 teaspoons of bi-carb soda. I don't think they like the new set up much but they are still uop and about. Only put them in today when I realised.
The Ph is up (7.3-7.5) and I can't seem to lower it. Is it the bi-carb?Any further advice will be most welcome.
In anticipation

,
Bigbob.