Hi du3ce,
Subtletanks91 is correct, the more information you can provide the better, it will help us make an educated guess. If you can include any information about PH, dKH, and dGH it would be appreciated as well.
Here is a 10 gallon, low light (PAR=25), non-co2 tank that I dosed a modified version of the Estimative Index (EI) of ferts along with Excel (actually glutaraldehyde). The PH was 7.0, the dKH was 1.0 (very soft), and the dGH was 2.0 (also very soft). Hope this helps! The Pogostemon erectus is in the left corner, the fine leaf stem in the middle is Rotala 'Bangladesh'.