Thanks, for the advise on spiders, I'll have it in mind.
And no, this is my second attempt on growing, my firts one was on soil, but didn't like it, this one is my first hydro attempt and looks good, has the same sie or even bigger than the soil ones, but un 1/3 of the time.
The white dots hasn´t disappeared, but i havent seen any other symptom, maybe it was just stress, who knows, I'll hang another pictures.