Yup, definitely biofilm then. That white stuff is the heterotrophic bacteria that's keeping your nutrient levels low by sucking up nitrate and a small amount of phosphate as it eats the organic carbon. You don't notice it as much with a BP reactor because the bacterial colonies form in the reactor and are continually sloughed off and skimmed out, but with system wide dosing they grow on every available surface.
I've seen people post on RC about needing to clean out their pipes every so often when they liquid carbon dose because the bacteria can get thick enough to reduce flow rates. The fact that your excess keeps getting dislodged is actually probably a good thing.
|