I don't know at the moment I'm afraid as I usually get someone else or my local lfs to do the tests for me as I don't have my own testing kit. Nothing ever comes back out of the ordinary though.
I changed my filters recently (leaving the others in to carry through the goodness)and that along with the meds cleared things up when I first posted about it. It's literally occuring the day after water change day everytime, of which I usually do around a 3rd once a week. I even moved everything else out other than the 5 clowns and the betta just incase it was possible overcrowding but no change.
I'm using pimafix as you suggested and things do improve, until that change of water.