High Nitrates in new tank

[IAReefer]

First post here. I started fishless cycling a new tank 2/14, and added Dr Timm’s and 2ppm Ammonium Chloride. Ever since I’ve started testing for Ammonia, Nitrite and Nitrate, my Nitrate had been reading 100+ with a Salifert test. Ammonia and Nitrite are always very low to zero. Any ideas what could be causing it, and how to correct it?

Tank is Innovative Marine Nuvo 40. 30lbs dry rock, 30lbs dry sand. RO/DI saltwater at 79 degrees. Kessil 360 Tuna LED (not running it yet).

 

[saltyfilmfolks]

How large a water change did you do after the cycle was started?

 

[IAReefer]

No water changes yet, just auto top off for the evaporation.

 

[saltyfilmfolks]

It’s reccomended to to do a very large water change after the cycle starts as the Ammona is converted to nitrate and there is nothing in the tank to use it. (Coral and large bacteria populations) and will generally lead to issues like cyano and algaes as they are introduced.

Do a big waterchange and follow up with some smaller ones for the next couple weeks

 

[OutsideBrian]

Nitrate will inaccurately read high of there are any nitrites. On 3/5 you dosed ammonia, did you test after that dosing to see what it went up to?

 

[saltyfilmfolks]

Nitrate will inaccurately read high of there are any nitrites

Can you explain this or provide a link?

 

[nereefpat]

Our kits use a Zinc reduction (or similar, like Cadmium) method for nitrate values. Nitrate is reduced to nitrite and quantified. Any nitrite present will interfere, causing nitrate values to read artificially high.

 

[saltyfilmfolks]

Nitrate will inaccurately read high of there are any nitrites. On 3/5 you dosed ammonia, did you test after that dosing to see what it went up to?

Our kits use a Zinc reduction (or similar, like Cadmium) method for nitrate values. Nitrate is reduced to nitrite and quantified. Any nitrite present will interfere, causing nitrate values to read artificially high.

So you think that with that low a nitrite number it’s causiing his no3 to peg out at 100 even though this doesn’t happen in the thousands of cycling and nitrate questions I’ve answered over the years rather than the the 120 drops of Ammonia the OP used to cycle the tank and hasn’t done a water change yet?

 

[WVNed]

I would be change the water right down to the sand
Then I would test again the next day.

 

[Eggs]

Perhaps it’s the test kit and a false reading.
But I haven’t answered thousands regarding test kits though.

 

[nereefpat]

So you think that with that low a nitrite number it’s causiing his no3 to peg out at 100 even though this doesn’t happen in the thousands of cycling and nitrate questions I’ve answered over the years rather than the the 120 drops of Ammonia the OP used to cycle the tank and hasn’t done a water change yet?

No, not necessarily.

I was simply attempting to expand on the nitrite interference of nitrate testing, since you asked it to be explained.

 

[redfishbluefish]

First off, welcome to R2R.

I see you started with dry rock. That rock needs to cure and those high nitrates are coming from the cure. I'd suggest large water changes....possibly weekly...until the rock is cured. Here is one case where 100% water changes are allowed. With rock that dirty, I suspect the cure will take longer than a month. The good news is that the cycle typically occurs within this time.

 

[IAReefer]

Nitrate will inaccurately read high of there are any nitrites. On 3/5 you dosed ammonia, did you test after that dosing to see what it went up to?

On 3/5 I dosed another 120 drops ammonium chloride, tested ammonia immediately after and got zero reading. Tested ammonia again today, and zero again.

It’s a 40 gallon tank, but it only took around 30 gallons to fill it. Dr Timms says to add 4 drops per gallon, so 4x30=120. I dosed it once when I filled it, and the second time 3/5 (120 drops each).

The nitrate reading has read 100+ every time since the first test. I’m just surprised it is that high, wondering what caused it and how to correct it. With THAT much Nitrate, is the cycle done? Thanks all!

 

[IAReefer]

First off, welcome to R2R.

I see you started with dry rock. That rock needs to cure and those high nitrates are coming from the cure. I'd suggest large water changes....possibly weekly...until the rock is cured. Here is one case where 100% water changes are allowed. With rock that dirty, I suspect the cure will take longer than a month. The good news is that the cycle typically occurs within this time.

This makes sense, thanks. I wasn’t aware that mined dry rock would produce nitrates, always learning something new!

 

[RIreefGuy]

I would take a sample down to your LFS and have them test it too. Could rule out a bad test kit. Never hurts to get a second set of eyes.

 

[OutsideBrian]

On 3/5 I dosed another 120 drops ammonium chloride, tested ammonia immediately after and got zero reading. Tested ammonia again today, and zero again.

!

If you dosed and tested for ammonia, then immediately got zero something is wrong.

 

[saltyfilmfolks]

You dosed a huge amount of Ammona and now it’s nitrate.

 

[IslandLifeReef]

Nitrate will inaccurately read high of there are any nitrites. On 3/5 you dosed ammonia, did you test after that dosing to see what it went up to?

Can you explain this or provide a link?

I don't have a link readily available for this, but @Randy Holmes-Farley, has mentioned this in several articles and posts. For reference, my nitrites were showing 1 ppm with a Red Sea kit and NO3 went over the maximum reading of the kit which is 50 ppm. Once NO2 went to zero, my NO3 immediately dropped to under 10 ppm.

 

[IslandLifeReef]

@IAReefer, if you only dosed your tank to a total of 2 ppm twice, your total nitrate from ammonia conversion should be less than 20 ppm. I would wait until nitrite reaches 0 ppm before testing nitrate. If your nitrate is still high, I would verify that test with another test of a different brand, or at your LFS. If the reading is still high, you have another source of NO3 in your tank.

 

[Lasse]

I don't have a link readily available for this, but @Randy Holmes-Farley, has mentioned this in several articles and posts. For reference, my nitrites were showing 1 ppm with a Red Sea kit and NO3 went over the maximum reading of the kit which is 50 ppm. Once NO2 went to zero, my NO3 immediately dropped to under 10 ppm.

Its right. If there is nitrites in the water - nitrate will give a false reading . The false reading 50 to 100 times higer than the nitrite reading. It means - if NO2 is 1 ppm - NO3 reading can be over 100 ppm. I differs between the brands and the explanation is like this

Our kits use a Zinc reduction (or similar, like Cadmium) method for nitrate values. Nitrate is reduced to nitrite and quantified. Any nitrite present will interfere, causing nitrate values to read artificially high.

Sincerely Lasse