The thing is I already suffered from calcium lockup by low pH in two different crops. Using the same soil, one from my zone (Growmix multipro), a mix of perlite, vermiculte, compost and moss peat. Tested de pH: firs crop 4.6-4.8, second crop 4.2-4.6. Humidity 40-50%, temp 23°C, medium-hard tap water, fertilized with Top-Crop (spanish brand). Lights COB leds white+full spectrum (600w per square meter). Strains from requiem seeds and royal queen seeds. Also, and I don't know if its important, lights were off very often for multiple blackouts in the area. The timers got delayed as well. I've been using this brand for almost 3 years and nothing happened before... What do you all think?