My BGK is rubbing against rocks, wood and substrate. I have a 55G tank with the Marineland 350 filter. I have 5 small tetra, 2 dwarf gourami, 1 Columbian shark, 1 angel, 1 stripped Rafael catfish, 1 gold algae eater, 1 bristlenose algae eater, 1 Trinidad pleco. My last water test was: PH -...