Well your nitrate levels increase as bacteria colonize the media in your system. Ammonia is introduced, either from your fish or from some non-living source, a certain type of bacteria turn that into nitrites, and a second type turn that into nitrates. The process of getting those bacteria colonies established will take weeks. If you have a running aquarium or access to a clean natural watercourse (creek, river, etc.) then you can inoculate your system with gravel from those and it will speed it up.
Thanks for joining the Aquaponic Gardening community! I hope you find it a fun place to explore aquaponics. There is a real blend of experienced and new aquapons in this community, so please don’t hesitate to get in there and start asking questions. Everyone is quite happy to help out new members – no question is too basic.
A great place to start is to read the “How to Use This Site” link on the upper right corner, “Start Here” section of the Main page. You might also find the “Aquaponic Gardening Rules of Thumb” guidelines helpful.
Please participate and check in with us every day! We are constantly posting news about aquaponics and the good food movement.
Thanks again for joining us, and I look forward to getting to know you.