Kann mann das irgendwie aufhalten oder verlangsame...

I'd dial back the N ~10% and see how it goes. looks a little dark underneath. Maybe, a bit low in Ca? But could also be from any 'boosting' of p/k too and causing it to be locked out as opposed to physically not enough present. As you get to late flower, you also have senescence occurring. So, it's a bit difficult to give any certain answers with limited information. Heck, the chlorosis at the top could be slightly too much light at the top, but you'd probably see other symptomsm prior, like singed pistils or the fan leaves would be very tight with overly tight node spacing etc... Like the above, you take all the possibilities and start eliminating them based on all the info you have. How it progressed is important. bottom line, the formula (soilless) or supplementation(soil) is out of balance for a period of time.. hard to know what symptom is lockout or an actual deficiency in these cases.