Why do I get a bacteria bloom everytime I do a water change and/or clean the gravel?

Question

Hi - thanks for reading. I have a 10 gallon and a 20 gallon aquarium that is established and has been through the cycling process long ago; however, recently when I do water changes and/or clean the gravel, the water gets white cloudy which I assume is a bacteria bloom. I don't understand why this is. I have one betta in the 10 gallon and some tetras and 2 ADFs in the 20 gallon. I have another 10 gallon with one betta that this does NOT happen when I do a water change and/or clean the gravel. Any advice on how to prevent this? I suppose the "cure" is just to wait it out but I hate to think that my fish are being stressed out everytime I change the water. Also, I only do a 25% water change. Thanks!

Answer 1

As time goes by bits and bits get  stuck in your "deep" gravel. Bacteria spawn there that eat wastes by distracting the gravel you move the bacteria and their food supply. If your gravel is very old, I would change half of it for new gravel to not over populate it and it would probabily lessen the bacteria.

Some fish(or once in a fish natural life) high currents disturb the rivers, ocean,..ect. bottom and causes the debris to split out. So theya re not harmered or stressed by this unless your tank goes form clear to milk..

Answer 2

I have hard water where i live, and when i do a water change it clouds the water. It just takes a bit for the limescale to settle/ get sucked into the filter, then the waters fine. Same when you clean the gravel, as you would stir it up :)

Answer 3

Try only doing 10% water changes weekly and only vacuum half the gravel every other week.  Your tanks are not over crowded at all and those fish/frogs would not be creating a lot of waste.  

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