Black bits floating around in my brand new tank!?!?

[PinkDiamond]

So I've had my new Eclipse 5 gallon corner tank set up and going through a fishless cycle for about 40 days now - I did a large water change today and when the water was stirred up, there were black particles floating all around in the water! They range from very small (think large bits of dust) to a bit bigger, and there are so many of them! I gravel vacuumed a bunch of them out during my water change, but many more were stirred up in adding the new water! And I can see that the edge of the filter itself nearest the input from the tank is black tinged, making me think it's been filtering these black bits out already. But it's far from getting all of them!

Does anyone know what this could be?? I have no decor in the tank that could have fragments falling off of it, and this is not gravel dust (my gravel is purple, not black and was rinsed ridiculously before I put it in, and the black bits float a bit more lightly than gravel particles, which I've seen in other thanks)

I'm hoping it's something harmless like carbon from the filter (at least, I assume that's harmless....). Any input is uber appreciated!

[iheartmyfishies]

It sounds like carbon from the filter media. Make sure your cartridge isn't ripped or anything. If it is you should replace it.

[okijapan]

Sounds like carbon to me as well.

Make sure you rinse the filter cartridge very well in a bucket of de-chlorinated water before you put it in your filter.

To avoid this problem you could do what I and many others do. Cut several of the black plastic slats on the back of the filter with a hobby knife and remove the carbon. It is really not necessary except when you are trying to remove medications from the water.

[dr2b]

Out of curiosity, did you rinse the gravel well? I have the same tank, and I have never had an issue with my carbon filters doing that. But as okijapan said, make sure you rinse the carbon filter very well before you put it in the water. I do see little black pieces come off when I rinse my filters before putting them in.