Icky Output Tube (Canister Filter Related)

[follicle]

To make a long story short, I ran into problems with my canister filter leaking, so I had to replace all of the green rubber tubing included with my Eheim 2217 filter, with clear tubing from a local hardware store. The filter is to back to working normal now, but I've noticed something odd.

It's been running with the new tubing for close to a month now and I've noticed that some reddish brown gunk has begun to coat the insides of both the intake and output tubes. It's not thick, but it's certainly enough to see it. The tank water is in ship shape – as clear as can be.

I guess where I'm confused is why is there nasty gunk collecting in my output tube? Is that normal? Shouldn't that water be clean since it has already run through the canister?

Any input would be appreciated. Thanks!

 

[sumpnfishy]

Not sure what it is but I've always had that on mine too. I think it's just the usual slime that coats the inside of filters, you just don't see it normally. It's never caused me any issues in the 2 years I've been running mine.

 

[An t-iasg]

When I had a canister filter I noticed this slime/sludge in my tubes also. It never caused any problems for my filter or tank either. It wasn't very nice to look at but my canister was under the tank in a cabinet so it wasn't in view when you were looking at the tank. I moved the tank so I decided to replace the canister tubing. My tubing was clear (what came with the filter) and I replaced it with the green Eheim tubing. After a while - maybe a few months - I began to see gunk coating the tubes again. It doesn't seem to be a problem unless your water flow is reduced, but if you wanted to replace the tubing whenever it gets too unsightly I think that would be ok.