Autopot Systems are designed with the plant in mind - to water and feed in a sophisticated way. The Autopot Smart Valve was developed to control the water level to ensure your plants receive the wet-dry cycle it needs to flourish.
Watch how it works here: https://youtu.be/w7-rouGxULo
The Smart-valve allows the fluid level to reduce before it then refills. When connected to a low pressure water supply or gravity tank, the Smart-valve opens to allow water to enter the bottom of the growing container to a set depth (approx 35mm). It then closes and stops more water from entering until the original supply has been used up by the pot.
This absorption is achieved by capillary action that happens in the growing medium. Once the water has been absorbed to the extent that the water under the Smart-valve has gone, the Smart-valve re-opens and another supply of water enters the growing container. This process is how wet-dry cycles are controlled by the pot's own rate of consumption.