white film of bacteria in pipes.

[Jesseliu13]

i dont think you have enough flow through the tubes vs the bioload... i have 10x flow and i have never had any kind of gunk like that in my tubes....

 

[markstrimaran]

I am flowing 500 gph. 3/4" ID. hose. On a 40 gallon sump and tank. I would think, that would keep them from getting too thick.