Did a couple test with the API test kit and it would appear that the result may vary greatly depending on solution #2, which need to be shaken for 30 seconds before use.

The vial on the right was not, and the result indicates 0.

http://i635.photobucket.com/albums/u...g/IMG_2744.jpg

If you have been using it a lot without shaking then your test solution will not be the right chemistry anymore and you may want to get a new test so you will have more accurate results... It will still give you a yes/no but it will say that the concentration of the nitrates is higher then actual.

Little did I know that when I added my air diffuser I would turn my algae into a rotisserie.

[youtube]http://www.youtube.com/watch?v=aUrbaAiBFoo[/youtube]

Haha, that looks awesome. Its so perfect.

Thats also the best way to ensure distribution of nutrients and exposure of all the algae's surfaces to the light. Algae should be rotated, partiularly cheato, which functions better under rotation.

Plants do need a 'shut-down' time from photosynthesis (all true plants do). During that time they (most) engage in cellular respiration (like animals), and also exchange nutrients, etc... If you put a cactus plant in 24hr light, I can tell you right away it will die as it's stomata ('pores') will be closed and it will not correctly exchange nutrients. So I agree with the prior suggestions, maybe you want to try at least 6hrs off (with your light), and see how that does.

Thanks for sharing!

Chris