Какви са условията за използване на PH уред за киселинност на аквариумната вода

 the conditions of Using Aquarium Water PH Acidity Meter as below:

(1) the environment temperature (0 35) degree ;(2) the relative humidity is not more than 80 percent ;(3) measured solution temperature: (5 60 degree );(4) power supply: four 5 alkaline battery;(5) no significant vibration;(6) in addition to the earth's magnetic field without  external magnetic field outside interference.