Hey TPT,

My aquarium is sooo cloudy! Yesterday I took the Eheim Classic 250 filter apart, and cleaned out the pads (in aquarium water that was in a bucket). Then I did about a 90% water change and started the filter back up. Now all of a sudden the water is super cloudy!

Any advice in fixing this problem would be greatly appreciated!

Thanks!

I always change 50% of the water once a week (well lately I've been slacking off some), unless there's some emergency, I guess.

If the water is not green, it might be a bacteria bloom, which goes away by itself when the food source is exhausted.

That is a pretty big change to make at once. I try to do filter maintenance monthly and usually when I am changing no more than 50% of the water. That still may be a bit too much all at once if your tank is less than 6 months old. Age usually creates stability. Also having a second filter as a redundant system is handy so you only disrupt one filter at a time.

Sounds like a bacterial bloom to me. It should clear up within a few days.

Your bio-media, likely a pad in there for that filter, is never supposed to be disturbed
according to lots of people myself included The sponges/pads before it are supposed
to keep it clean enough to do it's job.
One person said in a reply to a similar issue..."Don't touch it till it falls apart."
It's supposed to look yellow. That's the bio film covering the bacteria.
You likely reduced the amount of those by 80%. That leaves much more food for those which were left. Given that they reproduce every 60 seconds(roughly) you have...
1 min=2...2 min=4...3min=8...4 min=16...5min=32 and if none die in an hr multiply
that 16 by 2 for 55 more times for your end result.
As long as the water is not green but rather white it will go away in 3-7 days +/-.