I think my tropica just got old, I got it a year ago in a big canister and maybe it is done.Tropica worked for me and others (ie. I got the tip to use Tropica from someone who was successful with it). I switched from APT to Tropica and my A. Pedicatella improved pretty quickly.
Sometimes it is not the brand but how much you dose? For a 60 litre tank, you should be dosing 0.8ml-1ml TSN a day. If you dosed more than 1ml/day that may have made things worse for A. Pedicatella.