Sump return shooting out white stuff when turned back on

[Foskett96]

Hello,
I have noticed recently that when I turn my sump return pump off and then back on again it is shooting out this unsightly white stuff that I have no idea where it Is coming from and cannot stand it. It is only happening when I turn the filter off and back on again. The tank has been set up for now over 2 years so I have no idea why it has started happening over the past week to week and a half.

 

[esoxlucius]

Don't worry about it, it's just a build up of bacterial bio film that forms over time on the inside of your return line. It's a prime place for the film to build up because you've got oxygen and food rich water gushing through there. When you turn the pump off the film can start to flake or peel off and so when you turn it back on you get a jet of it in your tank. Frustrating if you've just spent ages cleaning. It used to bother me so i started cleaning my return lines and this eliminates the problem. But nowadays i just leave it. The sudden unsightly cloud of gunk clears up in no time anyway. A see through return line seems to make it worse as well because the bacteria grows faster if the light can get to it.