Why Do a Run-Off Test?

Personally, I water to achieve a 10-20% run off (I use soil, however, but same principle). Taking your reads from your run off is pretty important... What we put in is not necessarily what comes out. That 6.0 may be 5.0 in the run-off if there's a pH maladjustment or many other factors, like poor microbacterial health, pathogens developing and so on. It's extremely important (in mine and many others opinions) to test your run-off constantly to ensure everything is Kosher. If putting in 6.0 yeilds a 5.0 result, lets say, it's your indicator that something's wrong and needs an adjustment. Left unchecked, problems will start to occur. Just my two cents. Good luck this week👍