Hi ! In a few days I ll do my fist flush in hydrop...

stop buying expensive marijuana branded products? Some are fine, but a ton are just overpriced and poorly engineered. it's probably poorly ph-buffered if you have constant problems. All those "final flush" or whatever products you are supposed to inundate your plant with at the end are 99% gimmicks. I leave the 1% for my lack of imagination, lol, just in case. The buds are grown and ripened by then, what exactly are these products contributing to that wasn't important the entire time the flower was being constructed? If it's expensive, it's probably bullshit, because the pool of ingredients for fertiliers (especially hydro/soilless) is typically cheap commodities. There may be exceptions to that rule, but also viable cheaper alternatives to those exceptions, and no discernable benefit between the costly/less costly options. "Flushing for harvest" does not change the constitution of flower in any way. You cannot flush out "minerals" from already built plant material. There is absolutely no excretion system in the plant that can do such a thing. If you have any toxicities or deficiencies, react accordingly.... Can you let a plant cannibalize itself at the end and save yourself the trouble of mixing up fertilizer? Sure, but only if the canopy is strong enough to provide the necessary nutrients. Ca is something needed at all times. if you only include it occasionally, that's a mistake. Depending on your tap water, you likely need to include around 100ppm of Ca. If something is further impeding its availability, even more will be needed -- this last context can cause a domino of negative effects of Ca levels need to be too high around roots to remain available. If you need a ton more than ~100ppm of Ca to avoid symptoms, chances are something else is up way too high and that's the cause of Ca issues. "Mulder's Chart" can help with this type of context -- usually can only discern such a context in hindsight after the wrong diagnosis and reaction. Your picture shows both potential deficiency and toxicity, so the overall formula is probably out of balance in more than 1 way.