Riego Foliar de la Muerte MOLD

That is not mold buddy that is salt build up i think :) I assume your using mineral nutrients. I wouldnt advise foliar feeding in dark periods it may let light in. anyway i use a foliar feed for 3 weeks and i try to do it just before the lights go off as your right that plants do absorb better at night because it opens stigmatas in the leaves more. amyway it is very very rare to get root rot or mold in hydroponic systems like this as the water is always moving so there is no place for it to settle :)