Gotcha. Consistently monitor ORP is the best way (and complicated too) to maximise the denitrator effectiveness. For manual dosing, finding the balance of carbon quantity and flow is quite simple. Unless your flow is very high, the carbon should be fully consumed internally thus no blooming. A simple no3 test (display and effluent) is good enough to give you the idea of flow/carbon ratio, and surprisingly it never failed to impress me. The only thing I really wanted to know is what are the bacteria that came out from the reactor that corals loves so much. Night time PE is super crazy, especially when there is major blooming happening (significant drop on effluent flow).
Speaking of dragonets, the trick is to pile up small rocks as safe haven for pods to multiply. They fed on planktons, in my case left over foods and detritus are abundant. I have a fat mandy in my 75G and at night there are hundreds of pods all over the place.
