hi, my boss recently bought a new 160ltr tank on a stand! he washed all the filter and the tank out and put his fish in it but overnight they died! i had a look myself and all the temp the ph and evrything was fine and he also took it down for a multi chemical test at our local fish shop which all came back good! hes tried new fish several times and same thing keeps happening! its got me stumped!! anyone got any ideas as what could be goin on!???
Are you even adding water conditioner?