Nitrates value doubled within 3 days

[Kayzah]

Hi there,

Last Friday, I have introduced my first fish (Premnas Biaculatus) into my tank (RSR 170). There is no other livestock in the tank.

100% dry rocks.

Just before introducing the fish, I did a large water change. Almost 50% percent of the total volume, after which my parameters were as follow:

- Salinity: 1025
- T°: 25° C
- Nitrites : 0
- Nitrates: between 10 and 25 ppm
- PO4: 0.2 ppm
- pH: 8.3
- Kh: 9.6

Three days later (Monday) I checked Nitrates and found out that the values had doubled. I could read somewhere between 25 and 50 ppm, or even between and 100 ppm (I have difficulties distinguishing between the different purples of the salifert test kit)

I'm surprised because I cleaned everything when I did the water change. I mean I cleaned the black filter foam and placed a clean filter sock into the tank. I repeat this operation every three days. I do my best to look after nitrates.

To make sure I don't overfeed, I feed my only fish with pliers. (OCEAN NUTRITION Flakes)


My skimmer (DELTEC 1351) skims very very clear color (evidence that the water is not that polluted). I even remember the foam being much darker when there no fish in the tank.

I try to be careful regarding Nitrates since this was main cause why I left the hobby a few years ago. I learned from my mistakes.

I have a 5-stage RO/DI system. Nitrates are undetectable in my RO/DI water.

Do you guys have an idea about what might the cause of this nitrates rise?

I'm planning on doing another large water change tomorrow.

I have already ordered NOPOX, but I'd rather know the reasons behind that problem before adding any stuff.

Thank you for your help.

Kay

 

[Randy Holmes-Farley]

Don't overreact to what might just be a test issue. Just keep monitoring it.

 

[Kayzah]

Unfortunately its not a test issue.
Would it be a good idea to do another large water change?

 

[ZachR32]

I would use another nitrate test kit for verification. I don't see why you would have that big a spike from a clownfish unless you're really overfeeding. Either way I wouldn't worry too much short term, your tank will adjust

 

[Randy Holmes-Farley]

Unfortunately its not a test issue.
Would it be a good idea to do another large water change?

How do you know? Even if it is accurate now, was it 3 days ago?

In any case, it’s not an emergency so verify or wait and watch before doing something that may not be needed or desirable. Nitrate too low is worse than nitrate too high.

 

[Kayzah]

Thank you all for your feedbacks.
I really appreciate.

I'll just keep watching.