Im thinking the drop to 60 for a couple weeks has weakened them. try dosing the tank.
PimaFix
Treats cotton-like fungal infections, and both internal and external bacterial infections. PimaFix harnesses the unique antifungal and antibacterial properties of the West Indian Bay Tree (Pimenta racemosa) for a safe and natural remedy; prevents the development of resistant strains of disease-causing organisms. Will not discolor water, affect biological filter, or pH during treatment. Will not harm aquatic plants. For extreme cases, PimaFix can safely be used with MelaFix to provide the added benefit of quick tissue regeneration and wound healing. 8 oz doses 400 gallons.
MelaFix
Contains the natural botanical extract from the Tea Tree (Melaleuca), an excellent alternative to resistant strains of bacteria that are unaffected by traditional medications. Treats bacterial infections such as red ulcers, fin and tail rot, cloudy eyes, mouth fungus, and others in as little as 4 days. Also heals open wounds, ulcers, and damaged fins. Doesn't affect pH; safe for invertebrates. MelaFix Marine can also be used with corals to control bacterial infections, reverse coral degradation and remove parasitic flatworms. 8 oz MelaFix treats 480 gallons of marine or freshwater. 64 oz MelaFix is a concentrated formula and treats 19,000 gallons. 8 oz MelaFix Marine treats 474 gallons marine water.