Important Question

[Tim13]

Hi I need to know what the right answer is to my question. EVERYONE says something different so I want to see what everyone has to say.

Do water changes during the cycling process prevent the growth of beneficial bacteria and prevent the tank from becoming cycled? And I'm speaking of a fish- in cycle.

I have heard this from many people and I want to know the truth. Is there anyone who has cycled their tank with fish in and did water changes during the process and successfully cycled their tank?

 

[erk628]

Yes you can! When I first started I didnt really know about cycling but aday or two after I had my tank set up with fish in it I found this forum. So since I already had fish I just did water changes everyday to keep the ammonia ans such down and it went trough the cycle. It did take longer but it got done.

 

[holidayinn]

With Fish-In Cycling water changes are a must.

 

[ellena]

There is some truth to both sides of the argument. You need to do water changes to keep ammonia levels low enough to not harm the fish. But you don't want to remove all ammonia as then the bacteria will have nothing to eat and a colony won't be able to establish. The sticky on fish in cycling says levels below 0.25ppm are safe for fish, so that's what you should be aiming for.
So you need to use a test kit and work out how often and how much water you should be changing.

 

[Matthew Lee Newell]

water changes during a cycle are fine,
just make sure its only like 20% water changes because you must make sure you keep some of the bacteria in the water.....
if you were to do 50+% water changes you maybe removing too much

 

[Geoff1991]

Water change as much as you want. Even though your test kit reads zero, there are still trace amount of ammonia in there, as with all water. Just so low your test kit isnt picking it up. But if you water change enough to keep ammonia at zero on your test kit, the bacteria will still colonize. And during the fish-in cycle, you want to water change enough to get your ammonia level down to a zero reading on the test kit.

This trace amount is all your bacteria needs to grow. Just make sure you dont temp/pH shock your fish.

 

[arobinson1984]

Totally agree with geoff here

The cycle only requires trace amounts of ammonia in order to progress, amounts so small that they are not even detected on a standard test kit. You should always aim to keep the ammonia / nitrite below 0.25ppm, preferably 0

Remember, even in a fully cycled tank, there is always ammonia present, just in such small amounts that your test kit will return a result of zero!

Andy

 

[coldcazzie]

http/www.fishforums.net/index.php?showtopic=226664

If you don't do the water changes you'll poison, maybe even kill, your fish. The amount of ammonia produced by the fish and the amount of ammonia eaten (for want of a better phrase!) by the bacteria isn't going to change because you do a water change. So long as you keep the levels low (preferably 0) the fish won't suffer too many side-effects, and the cycle will still continue.

Even if it does take longer I'd rather have healthy fish than have spent money on new pets only to kill them through my own stupidity later.

 

[sjolliff]

During my fishless cycle i dont change the water at all
as there can be advantages in not

 

[Geoff1991]

^ Yeah but thats not to be confused with a fish-in cycle, where you face killing/ fish if you dont do water changes of about 50% 2/3 times a day

 

[dthoffsett]

water changes during a cycle are fine,
just make sure its only like 20% water changes because you must make sure you keep some of the bacteria in the water.....
if you were to do 50+% water changes you maybe removing too much

Actually about 90% of beneficial bacteria lives in the filter so large water changes won't affect the numbers. You'll want to do as large of a change (or multiple changes) as it takes to keep the ammonia below 0.25ppm .

 

[OldMan47]

Tim, the only concern you have during a fish in cycle is caring for the fish. The cycle will take care of itself. If you keep the ammonia and nitrites as low as you can for the fish's sake, the cycle will move about the same speed and the fish will survive with little harm. I have seen the same misleading things posted on lots of forums and have made my own attempts to help them understand the actual science involved but when they won't listen, or even think, due to preconceived ideas, I give up and come back to reasonable places like this one. There is some evidence, presented in the scientific section, that a fishless cycle will likely proceed slightly faster with water levels being kept low. It has been a while since I read through that thread so I don't remember all of the details.