PH of "super coco" mix

Realized I didn't put enough details. Medium mix 60% coco coir 25% Perlite 25% worm castings 2tbps per gallon of 70 % DTE 4-4-4 30% DTE 4-8-4 Coco was buffed with calmagic

You need the mesure both but maily the medium itself the mesuring of the run off is merely to know how much to adjust your next feed and also if your using an ec or ppm meter you can get a good idea of how much nutrients she is taking up also by knowing the ec level you set it at waiting until watering and then testing the run off though when your at this stage less is more I would even saturate the whole medium thats going to risk over watering a seedling and perhaps drowing it. If your asking for future referance fair enough im probably not the best person to say cause i am a dwc grower but I know all about ph as its a huge part of dwc growing. You should first check your medium then your water before you feed and then your run off after you feed but you know this is only when the plants will require full saturation of the medium which comes at a much later stage otherwise as stated you will run into over watering issues that will slow her down a tip for watering only water the base of the seedling and let it dry out then water again im talking like 40 mls of water thats all they need really aslong as your temps arnt too high :) anyway best of luck for this run :)