So far I have never had a problem with over watering. I think when the choppers fly over they just pause to laugh at my sickly grow. My friend calls it the Auschwitz grow - it gets just enough to survive. To say I have had water issues is an understatement. I hope to resolve this next year by having a spring professionally developed. Then I should have all the water I need and hopefully will need to use that index finger moisture tester. Batteries not included:smokin: