[Topick's choice] iBowl Aquarium Water Quality Digital Monitor, measures water PH, TDS, EC, Water Temperature, Air Humidity, and Air Temperature. The Clip, extended, and WiFi versions are available. 

1-year warranty included. 

iBowl water quality digital monitor is a 5 in one measuring device that displays all 5 of its readings on a LCD screen with the addition of a built in bluetooth transmitter to project readings directly to your phone via their app.

A stress free way of knowing

• when you may need a water change,
• Displays your tds of water 
• current temp of water
• Current ambient air temp
• Your constant pH of water

Please keep in mind you will need to calibrate the pH monitor if they are displaying improper pH values.