Hi Julio,
Diatoms are very small and you could not see them, until they bloom and there are many of them. Patience in this hobby is the VERY best thing you can have. If you have done everything right, test your water often... like every three or four days. After it finishs cycling, they will be where you want them. In the NORMAL course of keepin a reef, especially a nano, you will have blooms of various sorts. Understanding them and dealing with them is all part of the additiction.
Roland
