Friends, help me figure out what this is about!?

I had this on hydroponics, at the moment I think that the problem is in the bacteria in the air that is supplied to the roots, at an early stage it often gets sick. It looks exactly like this: first the leaves turn pale, then turn yellow, die and fall off, and it does not grow at this time. My decision is not to supply air to the roots for the first month, and then put a filter on the air pump from cotton wool at least. My last grow, speaks of the success of the operation)))