Nitrate is basically non-toxic but can cause stress if it is allowed to build up to high levels. At the start up of the tank it can be a great learning process for students by graphing the levels of ammonia, nitrite and nitrate on a daily basis for the first 2 weeks and then periodically afterwards. There will be a definite increase and decrease of ammonia and nitrite over the first 3 weeks before they reach undetectable or trace levels. Nitrate will continue to increase after this period and can be monitored before and after monthly water changes. Students can utilize the data to understand the nitrification cycle in aquatic ecosystems.
Students can also research the importance of N based building blocks in organisms.
After 48 hours the tank will be ready to accommodate a few oysters. If you add too many oysters at the beginning you are likely to have a tank full of dead oysters since a bacterial population has not been established to convert their ammonia wastes into non-toxic forms. Oysters may be acclimated to the tank temperature by placing them in a plastic bag and hanging them in the tank for 30 minutes. Add the bacterial conditioner at the same time you add the oysters. Remember to add only a few oysters the first week to allow the water to become biologically conditioned to the oyster waste products.