Large swings in nitrates

[Katze]

Hello everyone!

At the end of summer, with the community's help my largest issue with NO3 has been fixed.
However now I'm having a bit of general mess with it here is everything you'd need to know:

1.
During the 1st week of september my nitrate increased daily by +1 ppm
-> I created a well working refugium which now stabilised the nitrate
On September 5th the nitrate stopped at 28 ppm as a response to this new export

2.
A week later my father had to tend for the tank for 3 days. This complicated things:
He blew all the cyano off the rocks
-> now nitrate had a reading of 44ppm (Sept. 16th )

3.
I waited a week to see what happens -I fed the fish regularly as always I washed out the mysis
->NO3 was 45ppm (Sept. 23) -basically unchanged

4.
On the 27th of September I started dosing NOPOX, PO4, and bacteria
-PO4 was 0.23 ppm

5.
On october the 4th the NO3 was 25.6 ppm while PO4 was 0.03 so I upped the PO4 dosage to 0.05ppm/day

6.
Today (Oct.6th) I expected 7ppm nitrates with the changes measured, but little did I know what came next... today 35ppm of NO3 was measured

And this is the mistery, what could be the reason to this swing?
The only thing out of the ordinary is that I cleaned 1 DT glass panel from film algae, which was not even a lot!
I'm really puzzled right now and I do need assistance again

 

[Lasse]

Which test do you use?

What´s your nitrite concentration?

Sincerely Lasse

 

[Katze]

Which test do you use?

What´s your nitrite concentration?

Sincerely Lasse

I used a Hanna Checker HR for it.
As for nitrite I don't, I'll measure as soon as I get home, but I had never seen it over 0

 

[Lasse]

I use Hanna Marine Master by myself. It use the same method as the checker. Its rather liable and not as sensitive to nitrite as other methods are. But I have noticed that the cleaning of the tubes is very important. I use to prepare 2 tubes with sample. Calibrate with one. Check with the other that it really says 0. Recalibrate with the one I will use as sample and following the instructions carefully. Very high NO2 concentration may up to four double the NO3 readings but I do not think that this is the problem here.

My system that´s is rather high loaded can rise my NO3 concentrations with up to 4-5 mg/L if my denitrification stops or slow down - but it is a special designed system.

Sincerely Lasse

 

[Katze]

I use Hanna Marine Master by myself. It use the same method as the checker. Its rather liable and not as sensitive to nitrite as other methods are. But I have noticed that the cleaning of the tubes is very important. I use to prepare 2 tubes with sample. Calibrate with one. Check with the other that it really says 0. Recalibrate with the one I will use as sample and following the instructions carefully. Very high NO2 concentration may up to four double the NO3 readings but I do not think that this is the problem here.

My system that´s is rather high loaded can rise my NO3 concentrations with up to 4-5 mg/L if my denitrification stops or slow down - but it is a special designed system.

Sincerely Lasse

My lfs checks NO3 for me. What I found to be weird is that when the 25.6ppm reading was measured my salifert test showed 50ppm while the Hanna checker the mentioned one, it's color intensity (the cuvette) was not as strong as today's though (with the 35ppm reading). While today's salifert showed 50-25, backing up the checker's measurent.

[What I find important to mention is that the salifert test atleast showed a decline in NO3]

 

[Katze]

Okay so I came up with a plan:
On tuesday I'll ask for a test again
-If it says +35ppm we'll know that the test with 25ppm was absolutely a false reading
-And if it comes back < 35ppm then the 25ppm was still false but the 35ppm was true meaning that the nitrate is being reduced, and there is nothing to worry about

 

[Katze]

I use Hanna Marine Master by myself. It use the same method as the checker. Its rather liable and not as sensitive to nitrite as other methods are. But I have noticed that the cleaning of the tubes is very important. I use to prepare 2 tubes with sample. Calibrate with one. Check with the other that it really says 0. Recalibrate with the one I will use as sample and following the instructions carefully. Very high NO2 concentration may up to four double the NO3 readings but I do not think that this is the problem here.

My system that´s is rather high loaded can rise my NO3 concentrations with up to 4-5 mg/L if my denitrification stops or slow down - but it is a special designed system.

Sincerely Lasse

I measured NO2 and NO3 today:

NO2: 0 (salifert)
NO3: 35 (Hanna HR) - unchanged with carbon dosing?!
PO4: 0.00 -I daily dose 0.08 ppm -which is a lot and still reads zero

What's to come:
I'll dose 5 ml of NOPOX instead of 10ml and I'll increase the dosed PO4 to 0.16ppm

Is there anything else to do?

 

[Lasse]

Be aware that dosing PO4 can cause a ketchup effect - reading zero, zero, zero, zero and suddenly what ever - but high. As long as your 0.08 dose seems to get your corals happy - you may not exceed in some weeks or more - IMO.

Sincerely Lasse

 

[Katze]

My corals don't look the best anyway, it's probably due to the disproportionate state of nutrients.
Just to be sure I'll measure PO4 more often to prevent a runoff
Also what do you recommend to decrease NO3 ?

 

[Lasse]

You dose NoPox - it may decrease NO3 after a while. For the moment - use WC in order to decrease the NO3 or to have it stable around 30

Sincerely Lasse

 

[BryanM]

nopox reduces both N and P. You stated you have no phosphate now, so dosing NOPOX is counterproductive, as you need detectable levels of phos.

I also would not be worried about your "high" nitrates. 5-50 IMO, and others, is a fine place to be. If you want to lower them I would do water changes to reduce.

But you need to get phosphate above 0. .1-.3 is a good target.

 

[Katze]

Well I have multiple problems with NO3 being that high:
1. Hard to measure differences with Salifert test kits (I won't pay 90 euros for a hanna checker. I'm currently having my lfs to do these tests, but only for a small amount of time)
2. Shocks newly introduced corals
3. I can't keep deepwater acros in so high levels

But yes, I'm currently dividing my NOPOX dosage by 2 and 2x my PO4 dosage, I hope it will help if not... then I'll stop dosing NOPOX and dose PO4 as needed, furthermore in that case a waterchange or two is inevitable