Question About Water

[frapadoodle]

Okay, a question about all the advice about using water from a mature tank to jump start a cycle.
As I do a 20-30% water change weekly, and a 50% drain for a heavy clean, would not removing that much bacteria cause a mini cycle?

 

[Essjay]

Any advice about using tank water to jump start a cycle is wrong. Most posts that advise it are corrected by other members. The filter bacteria grow on surfaces, mainly in the filter media. There will be bacteria growing on all the surfaces in the tank but the majority live in the filter because the surface area in there is huge, and because the bacteria like constant water flow bringing food and oxygen.
 
There will be a tiny number of bacteria in the water, but so few that even a 100% water change won't remove enough to make any difference. Doing a water change won't cause a mini cycle.

 

[sadguppy]

You may be confusing advice on upgrading to a new tank - in that case you will want to keep a certain amount of water to make sure that the fish don't suffer PH shock, however you also need to swap over the filter media as this is where the vast majority of the bacteria can be found.

 

[benzenering]

Keep your new water parameters the same as the current parameters, temperature and pH to make water changes less stressful for your fish. Beneficial bacteria mainly live on the filter(s) not in the water.

 

[frapadoodle]

Thanks for the replies,
I agree with using existing tankwater for ph and dissolved minerals and such.
As well as using existing media.
Just concerned with the idea of using tankwater to instant cycle popping up so often.
Sorry, use the same tactics at the lfs before I trust the help.
I know with this many people on the forum, sometimes things will slip through.