Strange Cycle Results

[piranhaman00]

Hey all! No stranger to cycling but have a strange one!

180 gallon DT, 75 gallon sump.

Started with 60lbs sand and 50 lbs dry rock, added 50 lbs live rock from a different established tank and 8L of Seachem matrix, and 7 bottles of BioSpira. Basically an extreme overkill on biofiltration.

Added ammonium chloride to 2ppm, let it sit for 5 days and tested; NH4 0.25ppm (api) NO2 >5ppm(api) NO3 >100ppm(salifert).

So at this point all is normal, I test again 3 days later and read 0 for NH4 and NO2 so cycle complete, yay.

Today (2 days later) was looking at my api kit and remember how fun shaking the NO3 bottle is so I wanted to try it out and see how dark it would be, fun right? Haha well I got 30-40ppm NO3. Ah so that’s why I use salifert now...whip out the salifert and get the same results...

No way denitrification could be responsible for this loss of NO3? There is of course no additional NH4 going into the system. I am currently prepping a 200 gallon water change and wondering if that’s necessary...

Any thoughts? There’s some algae from the live rock but nothing extreme, refugium in place but no light, can’t figure out where that NO3 went

 

[Flippers4pups]

Hey all! No stranger to cycling but have a strange one!

180 gallon DT, 75 gallon sump.

Started with 60lbs sand and 50 lbs dry rock, added 50 lbs live rock from a different established tank and 8L of Seachem matrix, and 7 bottles of BioSpira. Basically an extreme overkill on biofiltration.

Added ammonium chloride to 2ppm, let it sit for 5 days and tested; NH4 0.25ppm (api) NO2 >5ppm(api) NO3 >100ppm(salifert).

So at this point all is normal, I test again 3 days later and read 0 for NH4 and NO2 so cycle complete, yay.

Today (2 days later) was looking at my api kit and remember how fun shaking the NO3 bottle is so I wanted to try it out and see how dark it would be, fun right? Haha well I got 30-40ppm NO3. Ah so that’s why I use salifert now...whip out the salifert and get the same results...

No way denitrification could be responsible for this loss of NO3? There is of course no additional NH4 going into the system. I am currently prepping a 200 gallon water change and wondering if that’s necessary...

Any thoughts? There’s some algae from the live rock but nothing extreme, refugium in place but no light, can’t figure out where that NO3 went

It can be absorbed into rock just as P04 can.

 

[piranhaman00]

Mm this is the first I ever heard of that, I’m assuming it can be leached into the water at a later time?

 

[brandon429]

Your cycle is 100% why for four years in the microbiology of cycling thread we do not factor anything but ammonia behavior in stamping a cycle closed. (And have zero failed cycles / dead fish killed by starting too soon in the thread, check it in the coming four years as well)

Nitrite doesn’t matter at all, despite video clips from MACNA this year saying it does, nitrite will never ever ever ever be an issue in gaining ammonia compliance in our thread or in reefing. When it becomes a factor like it’s been stated to be a factor since our hobby began, we will have a false start cycle and some dead fish to show. A four year pattern speaks for itself.



Nitrate is for algae and color tuning of corals. We cannot rely on getting nitrate readings to factor in cycles due to test error, denitrification though rare in a new setup can be a known character of live rock, uptake by resident algae when undergoing blended cycles (live rock plus dry rock in same system) all prevent us from using it to factor a cycle closed. Of course most cycles will indicate nitrate, and pretty high levels of it since the hobby has adopted arbitrary bottle bac instruction of 2 ppm dosed multiple times as a benchmark (2 ppm movement of ammonia is absolutely not required to prove readiness, any degree of ammonia movement proves it) and when nitrate is present, it does indicate oxidation happening, but so does ammonia.

Nitrate is merely a lucky second proof that isn’t required and when missing, has no more reflection on your cycle than the 20 threads I can drum up right now of matured reefs having to add stump remover to gain it. Fifty pounds of live rock and most likely wet packed sand will report cycled per our measures, and that blended portion already cycled will mask the readings from the uncycled dry portions until those areas take on full bac by association in a week or so

The only way live rock will uptake nitrate is by denitrification or binding by organisms anchored to it, there isn’t a storage and release mechanism for it in the calcium carbonate matrix like there is for phosphate...per Randy’s chem forum I’ve asked him that before.

 

[Samina]

When you measured before the cycle completed, nitrite was registering at 5ppm and nitrate at 100ppm. The problem is that nitrite in a system, it will skew the actual results of a nitrate test. Now that your tank is cycled and it’s resulting in 0 nitrite, you’ll be able to get an accurate nitrate result, which in your case is the 30-40ppm your getting. Which sounds about right for a 2ppm ammonia addition in the beginning.

 

[nereefpat]

When you measured before the cycle completed, nitrite was registering at 5ppm and nitrate at 100ppm. The problem is that nitrite in a system, it will skew the actual results of a nitrate test. Now that your tank is cycled and it’s resulting in 0 nitrite, you’ll be able to get an accurate nitrate result, which in your case is the 30-40ppm your getting. Which sounds about right for a 2ppm ammonia addition in the beginning.

Yes, this is the answer. The nitrite present in your first sample was interfering with the nitrate reading.

 

[piranhaman00]

Your cycle is 100% why for four years in the microbiology of cycling thread we do not factor anything but ammonia behavior in stamping a cycle closed. (And have zero failed cycles / dead fish killed by starting too soon in the thread, check it in the coming four years as well)

Nitrite doesn’t matter at all, despite video clips from MACNA this year saying it does, nitrite will never ever ever ever be an issue in gaining ammonia compliance in our thread or in reefing. When it becomes a factor like it’s been stated to be a factor since our hobby began, we will have a false start cycle and some dead fish to show. A four year pattern speaks for itself.



Nitrate is for algae and color tuning of corals. We cannot rely on getting nitrate readings to factor in cycles due to test error, denitrification though rare in a new setup can be a known character of live rock, uptake by resident algae when undergoing blended cycles (live rock plus dry rock in same system) all prevent us from using it to factor a cycle closed. Of course most cycles will indicate nitrate, and pretty high levels of it since the hobby has adopted arbitrary bottle bac instruction of 2 ppm dosed multiple times as a benchmark (2 ppm movement of ammonia is absolutely not required to prove readiness, any degree of ammonia movement proves it) and when nitrate is present, it does indicate oxidation happening, but so does ammonia.

Nitrate is merely a lucky second proof that isn’t required and when missing, has no more reflection on your cycle than the 20 threads I can drum up right now of matured reefs having to add stump remover to gain it. Fifty pounds of live rock and most likely wet packed sand will report cycled per our measures, and that blended portion already cycled will mask the readings from the uncycled dry portions until those areas take on full bac by association in a week or so

The only way live rock will uptake nitrate is by denitrification or binding by organisms anchored to it, there isn’t a storage and release mechanism for it in the calcium carbonate matrix like there is for phosphate...per Randy’s chem forum I’ve asked him that before.

Thanks for all the information! I missed that thread, I will check it out!

When you measured before the cycle completed, nitrite was registering at 5ppm and nitrate at 100ppm. The problem is that nitrite in a system, it will skew the actual results of a nitrate test. Now that your tank is cycled and it’s resulting in 0 nitrite, you’ll be able to get an accurate nitrate result, which in your case is the 30-40ppm your getting. Which sounds about right for a 2ppm ammonia addition in the beginning.

Yes, this is the answer. The nitrite present in your first sample was interfering with the nitrate reading.

Thanks! I did not know that NO2 would interfere! Makes a lot of sense.