# Water Change & Mini Cycle



## Thomas (Nov 8, 2005)

:fun: Will too much water change cause mini cycle or even a whole cycle of the tank?

I have heard that some people do 50-60% water change per week. Some even said they are sure doing 90% or more water change will not cause any problem. But then some people said doing more than e.g. 20% water change every day will cause re-cycling of the tank. Which one is correct and which one is wrong? What is the theory behind these belief?


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## Georgia Peach (Sep 23, 2005)

I would never reccomend a 90 % water change - I think that would certainly remove too much of the bacteria - as far as a 50-60% water change, I think it would depend on the stock load of the tank and all. I do a 25-30% change on mine once a week.


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## MyraVan (Jan 19, 2005)

There are little to no bacteria in the water, and as long as your new water is dechlorinated and the same temp and pH as your tank water, you can change as much water as you like without harming your fish. When I'm cycling a tank I'll do something like 66% water change if the harmful chemicals are too high.

If however you don't dechlorinate your water or match the temperature of pH, it's best to only change a little bit, like 10%-20% at most. If you don't dechlor the water that does kill the bacteria, and if it's not the same temp or pH it can shock the fish.


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## fishfreaks (Jan 19, 2005)

I'm with myravan. Most of the bacteria is in your filter


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## Damon (Jan 18, 2005)

Bacteria live everywhere in your tank. Gravel, filter, decorations, tank walls, plants etc... Not so much in the water column.


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## Fishfirst (Jan 24, 2005)

which is why you can do a large water change and not worry... however, your water chemistry does change if you haven't done a water change for a while (such as pH going up or down, different hardness, alkalinity etc) and thats where you run into problems. If you do changes regularly this is prevented and you have basically the same water that comes from you tap in the tank.


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## Thomas (Nov 8, 2005)

So... during cycle, do we usually do the same amout of water change ? Funny enough I have never monitored the cycle of my (first) tank because at that time I did not know anything about cycling at all. For my new tank, I did not need to cycle because I had good "seed" from the old tank.


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## garfieldnfish (Jan 18, 2005)

In one of my tanks I do a weekly 90% water change. All critters are heavy poopers and it takes this much water change to get most of it out. It has never caused a problem in the 8 or so months I have done it and both my ADFs and applesnails have provided me with offspring. The clown plecos in this tank have not yet but they are still juvies. But that is the only tank I would ever do this with. All other tanks get a 25% weekly water change and no more. I have a water purification system on my tab water so it is always the same quality and I do not have to add any declorinator. I just add some leafzone ferts and some calcium but it has not adversely affected the plecos a all as they have been growing and I never had a mini cycle.


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