Get a good digital PH meter if you dont have one, the others are near worthless along with the color tests...
The soils PH could be higher or lower than 6.5, that is why you check runoff...If he has no lime if the soil and the mix is peat based... his runnoff might be 6.8 or higher yet feeding with a solution of 6.5. The solution will maintain 6.5 but only until the other elements and the medium interact with it- causing drift. If feeding at 6.5 and the runnoff is at 6.5 you know the roots are in the zone.If feeding @ 6.5 and runoff is 8.0 you know there is a problem. Usually looking at the leaves will tell you there is a PH issue but that takeslearning and exp. Its OK to let the rootzone PH swing as it will when the plants feed. keeping it in the right zone without to much ph swing, while adjusting the feed solution back to the right level in small increments is whats important.
It doesnt matter what you do it matters what the person you are helping is doing and what they are working with to give the right advice.
Test runoff and adjust feed solution to compensate the PH in the rootzone, Use dolomite lime as a topdressing to help the drift and stay on top of the whats going in and out of the containers from now on. Next time you pot use just under a cup per gallon of DL in the soil or medium of choice to help the PH buffer itself later on in the grow....
Kudos!
