So you treated with appertex and spartrix two months ago, the life cyle is four weeks. So it is time to treat again, but with something different, like ronidazole and coxoid. Best wormers would be Ivermectin or Moxidectin. As for bleach I would use Milton as used for babies bottles. I put a splash in the bottom of the drinker 2/3 days a week. I would also use cider vinegar 2/3 days a week this will help with kanker and e-coli. Galic in with the cider vinegar will also help, or even on it's own. Try not to treat all on the same day and once you have got them right, I think you better start looking at your stock management. The loft must be bone dry, damp conditions will always cause problems even if you have a stream or river near by.