White Suspended Particles - Filter Medium?

[elcano]

Hi! Having some problems with a cloud of white suspended martial in my water.
I've searched the forums but found nothing that really covers this (i.e: no worms, algae, etc).
Photos:
http://www.edave.net/images/tank/IMG_1449.jpg
http://www.edave.net/images/tank/IMG_1450.jpg
http://www.edave.net/images/tank/IMG_1464.jpg

I've been away for a few years and my parents have been looking after my tank. They've had no such problems prior, but they also didn't clean my filter. (Eheim Pro 2224). Seeing as I did so a week ago, could this be distrurbed (breaking down) filter medium?
If so, would it be safe to change it all in one go or should I do a 50% swap and then a few weeks later do the rest?

I have put a bag of Activated Carbon in the filter but it hasn't done anything.

Thank you so much for you time!

EDIT: They're not bubbles. They go down all the way to the bottom and then flow upwards. :)

[Sully]

yep, suspended solids--lol. hate that when it happens.

have you been feeding them more?

i would slowly, over a period of weeks clean and replace media in filter. Rinsing mechanical first. First up i would replace the coarse filter media. Then the fine mechanical media.

i always mess with filter media slowly and a piece at a time. too paranoid about the bio filter.

[boofish2]

I've had this problem too. It looks like a bacterial bloom. What I did was 40% WC, cut down on the food (once every other day), kept the light off (I know it's not algae and this is probably not imperative -- just telling you exactly what I did), and changed the filter cartridge. After about a week the water was crystal clear again. Hope this helps! Good luck :)

[boofish2]

Pretty tank by the way! Is that a Siamese algae eater? Love those guys!