Skywalker haze free seed

Repotted into a 12.5L airpot and switched the light. 40% power and 35cm from the plant around 500 ppfd. -Day 3 veg. Gave some nutes today EC 1.1 PH 5.8 some yellowing on the lower leaves, propably a little bit under fed so i raised the EC little bit -Day 6 veg. I've been using my milwaukee PH and EC pens, i also have blue lab guardian montior. Plant was growing quite slow so i checked the PH value with the bluelab and i noticed that the milwaukee ph pen was 5.5 when the bluelab was 5.8 and both were just calibrated too. Luckily not that much of a difference but seems to affect to the grow a little bit. I think i'll trust bluelab more now on. I have never let the ph probes dry so there should be no problems. Also topped today and raised the power to the 60% should be around 600 ppfd at 45cm height