Green Growth and White residue in Filter

[Aiglos]

Hello, Curious question, I had visiters over yesterday and they were quite interested in my fish, they asked me what the green vegitation like growth in my filter was,  I didn't really know the awnser to that, I assume its algae correct ? I have a Penguin Bio-wheel 125, a Whisper 30-60 filter, a regent 10 and a Topfin 30 filter,I clean the filters about once every 2 weeks and it comes right back,  I also have a buildup of white around the filter, I assume this is just minerals from my water collecting, Should this be cleaned out ?  or is this nessesary in the biological filtering ? It doesnt seem to be effecting the fish, they are all happy and healthy and all my water parameters are perfect.. Too perfect sometimes ;-)

Thanks.

[BigDaddy]

If it is green and slimy and comes off in sheets, then that is blue green algae.

I get it on the output of my Mini on the apisto tank, but not in the tank itself.

And yes, the white residue is calcium and/or magnesium from the water.

[Aiglos]

BigDaddy> Yes its not in the tank itself its just in the filter interesting oki thanks, I better remove that,  the calcium and magnesium is not harmfull is it ?