I personally dont know, but i would suggest that you add water until it starts to come out the hole in the side. Stop watering and wait until the water stops coming out. Take that water and pour it back into the bucket. It should not come out of the side. Start to water again until water comes out of the hole again. Repeat the process until as soon as you start to water again, it comes out the side.
At this point, the growing medium is fully saturated and cant hold any more water.
This may take a few minutes.