AsNoriuanswered grow question 4d ago My view . Why grow in coco ( even if its part ) if you wanna go with almost slow release nute way. Add worm castings, plant will use it, no doubts. Bigger plants all very nice, little will overcome previous issues.
Again, from my own experience, those meters have huge accuracy margin, good grower shouldn't rely on cheap , worthless things. Put your efforts into watering pH control, not soil mix pH control.