High nitrates after cycle -- false positive from nitrites?

[cowfootball]

I started my cycle on May 5ish and wasn't consistently testing nitrates, only ammonia, until yesterday. It looks like my cycle is complete but my nitrates are quite high in-spite of several water changes (two 50% water changes and a 10% water change). I'm wondering if it's a false positive from high nitrites (>200ppm, the max hanna sensitivity) and if I should keep doing water changes or just leave it and drop some fish in.

May 5:
1.4 ppm nitrates
2.5 ppm ammonia

May 12:
1.9 ppm ammonia
44.9 ppm nitrites

May 13:
0.76 ppm ammonia

May 14:
0.16 ppm ammonia

May 15:
0.06 ppm ammonia
200 ppm nitrites (test max sensitivity)
56.2 ppm nitrites

May 16:
75 ppm nitrates
200 ppm nitrites (test max sensitivity)
0.06 ppm ammonia

I did a water change here.

May 16:
54 ppm nitrates
0.04 ppm ammonia

I don't think it's relevant to my question but just in case, I've been dosing AFR as well and as of today I'm at:

0.02 phos
404 calcium
7.0 alk
1395 magnesium

pH is in the ~8.3-8.4 range and salinity is 1.025.

 

[Garf]

I started my cycle on May 5ish and wasn't consistently testing nitrates, only ammonia, until yesterday. It looks like my cycle is complete but my nitrates are quite high in-spite of several water changes (two 50% water changes and a 10% water change). I'm wondering if it's a false positive from high nitrites (>200ppm, the max hanna sensitivity) and if I should keep doing water changes or just leave it and drop some fish in.

May 5:
1.4 ppm nitrates
2.5 ppm ammonia

May 12:
1.9 ppm ammonia
44.9 ppm nitrites

May 13:
0.76 ppm ammonia

May 14:
0.16 ppm ammonia

May 15:
0.06 ppm ammonia
200 ppm nitrites (test max sensitivity)
56.2 ppm nitrites

May 16:
75 ppm nitrates
200 ppm nitrites (test max sensitivity)
0.06 ppm ammonia

I did a water change here.

May 16:
54 ppm nitrates
0.04 ppm ammonia

I don't think it's relevant to my question but just in case, I've been dosing AFR as well and as of today I'm at:

0.02 phos
404 calcium
7.0 alk
1395 magnesium

pH is in the ~8.3-8.4 range and salinity is 1.025.

You can only get about 6 or 7 ppm of nitrites from 2.5 ppm ammonia, so 200 ppm nitrites is a wacky reading (I expect you mean parts per billion, not million). But yes, nitrites do in fact usually mess around with nitrate tests, as you state.

 

[Randy Holmes-Farley]

I agree with the above. You cannot have 200 ppm nitrite.

How are you cycling?

 

[Jay Hemdal]

I agree with the above. You cannot have 200 ppm nitrite.

How are you cycling?

That threw me at first, I’ve never heard of nitrite reaching that level. Turns out they are reporting in ppb, which is how the Hanna nitrite checker reads.

 

[cowfootball]

Sorry, yes, 200ppb on the Hanna.

I fishless cycled using Fritz TurboStart 900 and Fritz ammonium chloride. I definitely overdosed ammonium because I didn’t realize the Hanna maxed out at 2.5 and I had probably 6-7 ppm of ammonia at one point. I never diluted to confirm but I did two back to back 50% water changes a few days after I realized what had happened to bring it back into the readable range.

 

[cowfootball]

Nitrates are down to 47.8 this morning without any intervention from me, making me think that a higher nitrite reading is responsible somewhat here. Ammonia 0.00.

 

[Randy Holmes-Farley]

It’s hard to know how much nitrite interference there is without an actual nitrite value, but watching and waiting is a fine plan.

 

[Lavey29]

Nitrites are irrelevant in reef aquaria for the most part especially if your tank is producing measurable nitrates. Why would you be dosing all for reef in a brand new tank?

 

[cowfootball]

Nitrites are irrelevant in reef aquaria for the most part especially if your tank is producing measurable nitrates. Why would you be dosing all for reef in a brand new tank?

Yeah, I'm not worried about the nitrites themselves, just trying to understand how they interact with my nitrate test results and the best way to manage my nitrates before I start stocking.

I only started dosing AFR a few days ago to get alk/calc/mg up in the right ranges to get ready to put some frags in and to learn how my ReefDose works and to see how long it takes for AFR changes to be affected in the test results. Once I get the numbers OK I'll stop dosing 'till coral go in. I'm an experiential learner.

 

[Lavey29]

Yeah, I'm not worried about the nitrites themselves, just trying to understand the best way to manage my nitrates before I start stocking.

I only started dosing AFR a few days ago to get alk/calc/mg up in the right ranges to get ready to put some frags in and to learn how my ReefDose works. Once I get the numbers OK I'll stop dosing 'till coral go in.

You don't need anything other then weekly water changes for many months. Dosing that is going to get your tank way out of balance because it's adding elements you can't even test for regularly to establish a baseline.

 

[Lavey29]

Yeah, I'm not worried about the nitrites themselves, just trying to understand how they interact with my nitrate test results and the best way to manage my nitrates before I start stocking.

I only started dosing AFR a few days ago to get alk/calc/mg up in the right ranges to get ready to put some frags in and to learn how my ReefDose works and to see how long it takes for AFR changes to be affected in the test results. Once I get the numbers OK I'll stop dosing 'till coral go in. I'm an experiential learner.

I've been using the reef dose for 3 years. It works great.