If you need to test the pH level in a pool, spa or aquarium, our top pick would be the VIVOSUN tester pen. It is affordable and easy to use. Here’s more:
What We Liked
• Accurate (as long as you follow the instructions!).
• Easy to use.
• LCD backlit display.
• Includes packets to help you calibrate the pen.
• Includes long-lasting batteries.
What Needs Work
• Must be recalibrated after replacing batteries.
• Some users had issues trying to calibrate the pen.
• Durability could be better. We see scattered reports that it pen stopped working (the LCD display gives out, for example) after a few months. If you need a heavy-duty or professional pH meter that is more durable, see our next recommendation.