Not Rly Newbie But Still Have A Q

[coldcazzie]

Apologies if this is the wrong place to post - it seemed the most appropriate...

I recently discovered my pH had dropped to well below 6, and 2 weeks ago started small daily water changes to slowly bring it back up (tap water is 7.4), then last Sunday removed a carbon sponge from my filter and that afternoon my tank started a mini cycle.

So far amm has not risen above 0.25ppm and nitrite is still at 0. Am changing 25% water daily and testing at least once a day, sometimes 2 or 3 times, depending on circs.

My Q is: I've been reading through a lot of the beginner threads etc and seen a lot of people say that the nitrogen cycle in a tank that is going through a fishless cycle will stall if the pH drops below 6 - does this apply to a filter that is already mature? Ie. if the bacteria stop growing in a filter because pH is too low, do they also die off inside the filter if the pH is too low (I'm not talking like 1 or 2 here, but I think mine must have dropped to about 5).

I'm just wondering if raising the pH could have contributed to the mini cycle due to the conditions gradually becoming more hospitable to bacteria and them deciding to grow again?

Also, how long does a mini cycle usually take? I'm now a week in...

 

[OldMan47]

Hi there Cazzie. Usually a mini-cycle does not last very long. My last experience with one only lasted about 4 days. You could go a little heavier on restoring your pH with water changes but it is really not a crisis. The bacterial growth will greatly slow at a low pH but it should not kill off the bacteria. I would expect the bacterial colony to recover fairly well. Meanwhile you are doing the right thing to monitor and react to ammonia and nitrite levels.

 

[coldcazzie]

Thanks - I think I'm starting to come out of the ammonia spike, but will have to see. Nitrites have not budged yet though.

Random afterthought - I have a homemade filter (sponge & gravel in a tub with an air line type jobby) in my tank as well as I wanted to give it a kick start maturing - when I take it out is my tank going to go through another mini cycle for the same reason it's started this one? Ie. it's lost some of the bacteria...

So far it's only been in there 2 days and I'm hoping to manage to get it out today or tomorrow and into the QT... just don't want to prolong my fishes being subjected to poisonous living conditions any longer than is necessary!

 

[OldMan47]

A 3 day time spent in the established tank will do almost nothing to begin developing a new filter. I doubt that there is anything of value that you will lose by removing it. Unfortunately, there is little of value that such a short exposure will have developed in the new filter either. It may have slightly seeded the new filter if you will be continuing to cycle it in the QT.

 

[coldcazzie]

Good! Glad it wont do any harm being removed! And yes it will be going straight into QT and start fishless cycle then.

 

[waterdrop]

Apologies if this is the wrong place to post - it seemed the most appropriate...

I recently discovered my pH had dropped to well below 6, and 2 weeks ago started small daily water changes to slowly bring it back up (tap water is 7.4), then last Sunday removed a carbon sponge from my filter and that afternoon my tank started a mini cycle.

So far amm has not risen above 0.25ppm and nitrite is still at 0. Am changing 25% water daily and testing at least once a day, sometimes 2 or 3 times, depending on circs.

My Q is: I've been reading through a lot of the beginner threads etc and seen a lot of people say that the nitrogen cycle in a tank that is going through a fishless cycle will stall if the pH drops below 6 - does this apply to a filter that is already mature? Ie. if the bacteria stop growing in a filter because pH is too low, do they also die off inside the filter if the pH is too low (I'm not talking like 1 or 2 here, but I think mine must have dropped to about 5).

I'm just wondering if raising the pH could have contributed to the mini cycle due to the conditions gradually becoming more hospitable to bacteria and them deciding to grow again?

Also, how long does a mini cycle usually take? I'm now a week in...

Your above discussions with OM47 are good.. I just wanted to add another voice to say that I think you're coming to the right understanding about the pH and the bacteria. When pH drops to below 6.2 or so in a tank with a mature biofilter, the biofilter doesn't stop working, it continues working just fine. It's the -rate of growth- it would have -if- it needed to respond to newly added fish or some other bioload increase that would be slow. We have had reports of tanks running down at pH 5 and below and the bacteria were just fine. Its just the growth thing. In some ways too, a really mature biofilter that's several years old, with obviously strong colonies of both species of beneficial bacteria, is a pretty tough thing, compared to a fairly new biofilter.

~~waterdrop~~

 

[coldcazzie]

Thanks.

Must just be the loss of filter material that's caused the cycle then. It's now been a week and I'm still at about 0.25ppm of ammonia each day before the water change, and nitrite is still at 0. Will press on and cross my fingers for a change soon.