How long is my nitrite spike going to last?

[Bambithegirl]

Hi all. I am on day 12 of my fishless cycle, but I am doing at least 2 water changes of 50% or more EVERY DAY to keep nitrites down and adding amoonia up to 4ppm twice a day. If I don't do that I find my ammonia at 0ppm the next morning. The constant water changes are a pain plus I feel SO bad wasting all that water. Any ideas how long this stage will last?

 

[threnjen]

I'm not really sure why so many on here recommend WCes to bring down the nitrites.

If your cycle stalls at the nitrites stage, it's usually a pH problem.

I was taught to cycle differently than around here and my ammonia got INSANELY high before getting to the nitrites stage and then my nitrites were INSANELY high. Never WCed. low pH was the cause of my cycle stall. The day after I brought it back up to a normal level, my cycle continued.

I would stop doing the WC and stop worrying about off the chart nitrites. Focus on keeping your pH above 6.5 and your cycle will finish.

 

[Masha]

Another approach is to not dose quite so much ammonia. 5ppm is much more than your filter will need to process once the fish are in there. 2ppm is a good amount.

Regardless, prepare for the nitrite spiking stage to last a lot longer than any other stage. The nitrite processing bacteria are the slowest to duplicate.

 

[threnjen]

Regardless which method you use, you can easily and cheaply boost your cycling pH with baking soda. Just be sure to do the biggest WC you can when it's done before getting fish (which you would do anyway, to get rid of all the nitrates)

 

[molliwopp]

You shouldnt need to add 4ppm twice daily regardless of how long it takes to convert, the bacteria wont die off in that time, once a day is fine and keep the water oxygenated.

 

[threnjen]

I think she's doing it because she's doing two WCs. Just stop doing the water changes.

Also at this point just dose 2ppm ammonia every other day. I missed that part earlier.

1) 2ppm ammonia every other day
2) stop doing WCs
3) check your pH and add baking soda if it gets near 6.5
4) wait patiently
5) 100% water change when cycle complete

 

[Masha]

I know that Threnjen does not agree, but here is the reason for the water changes

Doing water changes to keep the nitrites in readable range 1) wont harm your cycle and 2) may keep it from stalling. The nitrospora, the bacteria that changes nitrites to nitrates, don't like too high nitrite levels, which slow down their already slow duplication rate.

In the end it's up to you who you decide to listen to of course! I've just seen far too many people posting on here with problems when their nitrite levels get too high, and I have personal experience of how doing water changes at this stage is not only fine, but helped to speed the cycle to its end.

Safest way would be to lower your ammonia dose, since then the spikes wont be so bad in the first place.

 

[threnjen]

Safest way would be to lower your ammonia dose, since then the spikes wont be so bad in the first place.

I think we can all agree on this!

 

[molliwopp]

I want to post my opinion on nitrite, never once has one of my tanks stalled because of unreadable nitrites, i always dose to 4ppm regardless of stock and the last 2 tanks i cycled only recieved one water change and that was the 95% change before fish.

My Ph did drop but never below 6. Im a cichlid keeper and my water is hard with a high ph of 8.3 which is probably why it never dropped below 6, lots of buffers and . Anyone with tap water softer and more acidic/ neutral you shud definitely keep on eye on the ph during.

 

[Delapool]

How high can nitrite go before the cycle will stall? 10ppm is the highest reference I have - although that was more of a warning.

 

[Rivercats]

Everyone's tank chemistry is different so what works for one may not work for another.

Often over 5ppm of nitrites is considered high and can cause a cycle to stall which is why when nitrites get to an unreadable level a WC or two is suggested to bring them down to a readable level on a test chart since too much nitrite in the water can indeed get so high the bacteria is unable to produce enough nitrobacter and just stalls itself. Not saying it will stall but quite often that is what happens. Reducing the amount of ammonia used is the best course of action so it won't process into so much nitrite. You have to find what works for your tank and if one thing isn't working try something else.

 

[molliwopp]

Yep, even though ive cycled without water changes and unreadable nitrites doesnt make it a cut and drawn case. My water is blessed with hard alkaline water which is the optimal conditions for nitrifying bacteria and there are plenty of examples of high nitrites stalling a cycle in different conditions, ive escaped a stall a couple of times dosing to 4ppm without changes but your water maybe different to mine like mentioned above.

 

[Delapool]

So a combination of things perhaps?

Temperature, kH / ph + nitrite level?

I must say increasing kH sounds easier then a water change. I guess this would change tank specs quite a bit before final water change - wonder if bb are sensitive to ph changes?

I did see a reference last night on the amount of carbonate consumed by bb. Will see if I can find it again.

 

[molliwopp]

I wonder if bb are sensitive to ph changes?
.

You know what i would be interested in that too, by sensitive to ph changes are you thinking about a drastic ph swing killing off bacteria? I heard they can be but have no personal experience with it or ph swings in general for that matter as ive never experienced one.

I do know that below a ph of 6 the bacteria fail to metabolise the ammonia. At 6.5 it consumes at only a 10-15% rate of that of 7.5- 8.5 so in theory, soft acidic tanks should require more filtration, a smaller bioload and a longer cycle than a hard alkaline counter part. And ive read anything below 5.9 infact converts ammonia to ammonium which is actually non toxic to fish.

Please somebody who know correct me if im making presumptions that are incorrect. And does anybody know anymore about this? also anyone know anything about ph swings killing bacteria themselves?

 

[Rivercats]

The only thing is when ph falls to 6 or less biological activity actually stops and BB do begin to die off.

 

[Delapool]

Yes, I was wondering if a large ph change can be bad for the bb as well. Maybe not if I understand Rivercats correctly.

For interest, I've attached the info relating to kh. I think if my tap water is 100ppm (g/t) for 500 litres. Then I have 50g of carbonates at start. Tank kh has been decreasing, more so it seems in the summer weather.

[FONT=&quot]"For every gram of ammonia oxidised into nitrate 4.8 grams of oxygen is used, 7.14 grams of calcium carbonate is used"[/FONT]

 

[Rivercats]

When ph falls to 6.5 or below biological activity slows but when it falls to 6 or below biological activity stops and BB begins to die off. I actually don't know if or how exceedingly high ph effects BB. IMO ph swings say dropping from 7.8 to 6.8 don't affect BB. Look at hobbyist who use CO2. They often have substantial ph swings daily.