After several years, my tank has developed hazy water and bacterial blooms twice after recent cleanings and water changes. I may have triggered the first one by replacing too much filter media all at once, although it was certainly no more than I had done before. A subsequent water change only made things worse, so I just had to wait it out and let it take care of itself.
The second bloom is even harder to figure out. I had just replaced the old HOB with a canister filter and the tank water now looked exceptionally clear. However, after a much smaller water change and filter media rinse in old tank water, a mild bit of haziness has returned again. It doesn't seem so bad this time, but I'm wondering what has changed recently. Over the years I've often done water changes as large as 80% without this reaction. Might anyone be able to figure this out? Thanks.