I have a 30cm airstone in my tank, and regardless of my attempts to keep the tank nice and clean, the tube to the airstone always seems to get really slimy and gross.
I know this is possibly regular and normal, however I was away for about a week and had someone else feeding my fish, so the tank wasn't cleaned at all throughout the week.
When I came home the airtube had a really digusting pink layering over it. It's not the first time it's happened either, so since it recurring I've decided not to put the airtube back into the tank until I can be certain it's safe, as I know that a general rule is that pink grime in cleaning things like bathrooms is usually dangerous bacteria, so I don't know if the same applies to fishtanks or what not.
I thought you guys would have more of an understanding than I, and lucky for you I posted a photograph so you don't have to rely on my terrible description. Here it is.
Any help is appreciated! Thankyou!