Cycled tank and water change question.

In a fully cycled tank is there any danger to changing too much water at once? Like how about a full water change?

 

I would say moderation is key. Certainly there are times when you may want to do a large water change. I would recommend against it if you can help it.

 

By doing a "full water change" you would most likely start another cycle since all the beneficial bacteria is gone.

 

The bacteria doesn't live in the water?

 

Yes the bacteria is in the water but more importantly is the water is aged and matured .. I have never changed water and I never have gad a problem I use carbon 24/7 and a diatom a few times a year .. But I'd not tell anyone to not do water changes But as mentioned already moderation is the key and to do a total water change would open the tank and its inhabitants to more then a few health issues ich comes to mind right off hand from the stresses .. I'd never change more then 10% at any one change..

 

Tinfury aren't you using NSW? I would think it would be different since in theory you are using cycled water. If using NSW, and I don't and haven't researched, but would think that you would not want to even have a cycle so the water should be replaced often. I want to try NSW when I'm closer than an hour from the coast.

 

Yea I'm using NSW. I don't understand what your saying. Ok I have two tanks, one is a 75 Gal that I'm trying to do the right way it's almost finished cycling everything is good except my nitrites are stuck at 0.25ppm. I also have a 10 Gal tank that I don't think I'll ever cycle. I keep chaning the water 100% in that one. I'm asking about the 75Gallon tank that is done the normal way with long cycling periods and a bio filter with LR and Sand.

Also, what exactly is aged water? Is that some chemical property of the water? Some bacteria living in the water column?

 

I also would never recommend changing no more than 20% at one time and that's if there is an existing problem you are trying to get rid of ex. nitrates. A small water change is efficient and there actually alot of articles out there suggesting that water changes cause unwanted stress to the inhabitants. There is no need to change that much water at once, I would say it is definitely dangerous, I would do only small water changes. I only do 10% every two weeks, I run a filter with sponge and carbon which is cleaned 2 x a week and I run a skimmer. My tank is very clean and with the very minimal of algae.
I think you will have continued problems if you do these huge water changes, you will disrupt the cycle.