Nitrites spiked after end of cycle PWC! HELP!

[Abemas]

Nitrites spiked after end of cycle PWC! Update!

So my "cycled" tank tested as follows last night:

Ammonia: 0
Nitrites: 0

Anticipating adding fish today I did a large 50%+ water change, added some clean rocks that have been sitting in their own tub of water, and put in a carbon filter just for kicks. The tank has been sitting for about 3 hours since the change and my nitrites are now .50 ppm. I have been nursing the tank with ammonia daily for 5 weeks and I believe I've seen all stages of the formal cycle. Any ideas why this sudden spike? Is it possible I stirred something up in the filter media or the rocks (which were oven baked) had some nitrite rich water on them?

 

[ejaramillo01]

Nitrites spike

I don't know the reason, but if your tank cycled good as you mentioned early, the Nitrites will go down pretty soon, maybe in some hours and you should be good to go with your fish.
IMO just re-test in some hours and I hope that you will see a 0 ammonia, 0 Nitrites...

Let us know

 

[neilanh]

Did you use a good dechlorinator when you did your PWC?

If so, then I agree... wait a few hours and you'll probably be ok.

 

[six2sevenproductions]

What type of water did you use? I had the exact same issue about a year ago. my nitrates would not go below .05 so I believed it was the RO water I used to mix my salt with. I switched to Natural SW and I purchased bad water. I was so furious. it was the only time i ever used natural water and I will never again.

 

[Abemas]

Just using straight up tap water with proper dosing of Prime. I checked the nitrate levels again last night and and then this morning. Last night was still showing close to .5 and this morning somewhere between .25 and .5. I went ahead and added just a bit of ammonia this morning (1 tsp) to keep the bacteria feeding. One thing I forgot to mention yesterday....I'm using pool filter sand as a substrate and did some aquascaping while the water was down during the PWC. Could I have stirred loose some nitrites from the sand while doing that? Also, I did check my tap water and its showing 0 nitrites out of the tap so thats not an option. Any suggestions on what to do next?

 

[neilanh]

I think you're fine. Good call on adding a bit more ammonia. If that all processes through and you get back to 0 ammonia and nitrIte by tonight I think you're all set and ready for fish.

 

[Abemas]

New readings this evening are as follows:

Ammonia: 0
Nitrites: Still .25!

I dosed at 7:30am with 1 tsp of ammonia so its been 13 hours since any new "waste: was added. Shouldn't this have been enough time to consume that? Arrggh! Any suggestions?

 

[mudraker]

I've had tanks do that when I thought cycling was done a few times.

I now only put fish in a tank if it tests clean for a whole week after its done cycling, because sometimes it just needs a few more days.

Yes, the patience it takes is maddening!

 

[Abemas]

Well after my "post- PWC nitrite spike" I continued to cycle the tank assuming it wasn't fully done yet. For the past 1.5 weeks I've been dosing with 3 tsp of ammonia (29 gallon) daily and after each 24 hour period both ammonia and nitrites have been zero. (Tank has now been cycling for 8 weeks.) Assuming I was safe, I did another 50% water change at 8:00pm last night (to prepare for fish today) and after allowing he tank to run for a few hours the nitrites had again jumped to .25. Assuming it was just from me disturbing nitrites in the substrate I added just 1 tsp of ammonia (to keep bacteria happy) and went to bed.

Its now been 12 hours since the PWC with the one tsp of ammonia added to keep the beasties eating and the nitrites are now somewhere between 0 and .25 (appears to have dropped a little from the test last night.)

Questions: After going a full week with daily dosing and daily tests showing zero for both ammonia and nitrites, is there any reason to assume the tank isn't cycled? Is my nitrite level post water change insigificant enough to go ahead and add some guppies today?

 

[neilanh]

I don't think giving it only 12 hours is a fair test. Give it a full 24 hours, especially for the nitrites. The general recommendation is to dose, wait 24 hours and if ammonia and nitrIte are at 0 you're good to go.

Remember that when you dose the ammonia, the bacteria that consume that immediately have a supply of "food" to eat. It's not until those bacteria convert that ammonia into nitrIte that those bacteria that feed on the nitrIte can even start their phase of the process.

 

[Abemas]

Problem Solved: Bad Test Kit!

Well out of frustration with my cycling efforts I went to the LFS and had them test my water. They just used a strip but she told me the nitrites and nitrates were sky high and not suitable fish. (They also gave me funny looks because I was doing a fishless cycle.) Anyways....I grabbed a new API test kit thinking perhaps the used kit I got with my aquarium off CL might be giving me false readings (it looked a big aged but I figured it was still good to go.) BINGO! Just got home and my tests were as follows.


Ammonia: 0 - .25ppm
Nitrites: 5.0ppm
Nitrates: 160ppm

I'm so frustruated I could spit nails. All this time I've been so careful and it turns out my testing components were simply inadaquate.

So, where do I go from here aside from a complete water change?

 

[neilanh]

Like I said before, let a full 24 hours pass by before you do anything. See what your water levels are at that point and then make the decision.

If you've been dosing as much as you think you have, then processing 5ppm of nitrIte in 24 hours probably isn't that far of a stretch.

 

[Abemas]

Okay we are now 48 hours since the last ammonia dose and 24 hours since I last tested the nitrites. Nitrites are now down from 5.0 to 2.0. Any recommendations?

 

[neilanh]

That's good news. I'll assume your ammonia level is 0.

Go ahead and dose ammonia again today. I think you're within days of the cycle being complete.

 

[Abemas]

Yeah it was zero yesterday so I didn't bother testing it again. How many ppm should I bring it up to?

 

[neilanh]

Dose the same amount you typically were dosing, just stick with that. Typically we recommend 3-5ppm, but don't do more than you were doing before.

 

[Abemas]

Success! Took me a few more days but the cycle finally finished. I ended up having to do two 80% water changes to get the nitrates to an acceptable level but the fish are in! Thanks for all the help. I've definitely learned my lesson regarding using a new test kit.

 

[maxst2]

Yay!

I had this happen to my 55gal as well. Pics of the tank!

 

[mudraker]

You get my applause for being patient and sticking to an admittedly frustrating process. You and your fish will be a lot happier for it in the long run!

Just don't forget do your weekly PWC to maintain optimum health for your fish.

Congrats.