You need more plant mass in that aquarium be it CO2 or non-CO2 setups. Plant at least 3-4 times what you currently have.
For non-CO2 setups, do not fertilize weekly as plant growth is really slow compared to CO2 setups. You really just need a rich substrate to get things going and feeding of your fishes to fertilize the plants.
Also, just topping up lost water will do.
Do a search on the forums for non-CO2 setups and you should get the hang of it.