Hi, I'm designing the attached aquaponic system and am trying to estimate the speed at which water will drain through the pipes. Basically, water enters the top of the pipe, then drains through roughly 5 feet of soil before it exits the pipe. Is there a way to estimate the speed at which the water will drain? I feel like it depends heavily on the type of soil. I was planning to use just your typical potting soil that you buy a a gardening store. Thanks!