Backyard Aquaponics
A place to discuss aquaponics

You could have a small flow running to the filter with an inline tap and only run it when nitrates are high. It would always be covered in water.

doing the research, fantastic. If u set up 3 different rsgs with taps above, u could isolate each one and work out which removes the nitrates best. A good assignment 4 the kids.

small problem, the RSG's are bacterial units. I'd be very surprised if they could last long periods with out food AKA nitrates. Much the same as nitrifying bactera.

Was reading through this topic and came up with a design for a re-usable RSG.

https://drive.google.com/file/d/0B4xuuaG9_hy4OVc2NF9LTUN1TFlJQkkxVGlqWEtVSXBNdUNR/view?usp=sharing