Confusion on Nitrites and Nitrates after Water Change

[pgallagher]

Hello, excuse me for the long post, I figured the more details the better!

I'm now on day #33 of my new 45-gallon tall freshwater tank and I think I'm more confused than ever!! I've been working through a fish-in cycling process after some bad advice from my LPS and lack of proper research on my part. My confusion is with my Nitrites and Nitrates. The Ammonia dropped earlier this week and is staying at 0 which is awesome!!!

I just got the API Master Kit (this is its first test) and here are my water parameters before my water change:
- Temp – 82
- GH - Between 60 - 120
- KH - 0
- PH – 6.5
- Ammonia - 0
- Nitrite reading – 5 ppm
- Nitrate reading – 80 ppm

I freaked out when I saw the Nitrite and Nitrate reading so high!!! So I decided to do a 50% water change.

Then I decided to do a test on my Tap Water:
- PH of the water straight out of the tap – 7.2
- Ammonia - 0
- Nitrite reading – 0 ppm
- Nitrate reading – 0 ppm

First off, this made me feel really good that it is clear of Nitrites and Nitrates. Secondly, I was really surprised to see the PH was considerably higher than my tank water. Could that be because of my sand substrate? It's CaribSea Super Naturals Moonlight Sand.

So I refilled my tank, added the Seachem Prime and sat to enjoy my tank for a little while... It was only 15 minutes after the tank was filled and settled again that I was curious and did another reading. Here's where it gets super weird!!!

Here are my water parameters 20 Minutes after my 50% water change:
- Temp – 82
- GH - Between 60 - 120
- KH - 0
- PH – 6.8
- Ammonia - 0
- Nitrite reading – 2 ppm
- Nitrate reading – 20 ppm

I just replaced 50% of the water and the Nitrite and Nitrate levels are high again!! How is this possible? What am I missing?

Any help is greatly appreciated!!!

 

[Myyyman]

Yes, your nitrate levels are through the roof! Not a good thing. Did you clean the sand thoroughly before putting it in the tank? And how often do you perform water changes? You can get things to lower nitrates but I would try to avoid chemicals. For the moment I suggest you familiarise yourself with the nitrogen cycle if you aren't already. Just keep doing water changes, maybe 25-50% every day until you've got low nitrate levels.

 

[Morpheus1967]

Your initial readings were:
0 Ammonia
5 Nitrite
80 Nitrate

You changed 50% of the water. One could conclude that your results should be:

0 Ammonia
2.5 Nitrite (50% of initial reading)
40 Nitrate (50% of initial reading)

Not sure why you are surprised with the results of the second test? The results are perfectly in line with the water change you did. In fact, nitrates are reading even better than they theoretically should be.

Edit to add: Your nitrites are still way too high for a fish in cycle. I would do another water change, and do enough water changes, whether it be daily or every other day, etc. to keep your nitrites under 1ppm.

 

[Morpheus1967]

Yes, your nitrate levels are through the roof! Not a good thing.

How is 20 ppm through the roof? That is a perfectly acceptable number after a water change.

 

[kallililly1973]

Also be sure to test your source water so you know what your adding back into the tank.

 

[TWiG87]

Also be sure to test your source water so you know what your adding back into the tank.

He did, there weren’t traces of anything in it.
Just like Morpheus said, your results are exactly what they should be after a water change. There’s not really a reason to get worked up about nitrates. If you test and they are high do a 50% WC and you’ll cut them in half

 

[mattgirl]

It is really good that you now are able to get more accurate readings on your tank. The 50% water change was the right thing to do. Another one today might be a good idea. I have to think the reason your fish are doing well at this point is because your PH has been so low and KH non-existent. These water changes and the crushed coral are going to get and keep it up to close to the same level as your source water so you need to get the nitrites down. At this point water changes are going to be the way to get them down. Even daily may be necessary

I have to think this tank is very close to cycled so the nitrites really should drop to and stay at zero fairly soon. Water changes will help that happen.

 

[pgallagher]

Did you clean the sand thoroughly before putting it in the tank? And how often do you perform water changes? You can get things to lower nitrates but I would try to avoid chemicals. For the moment I suggest you familiarise yourself with the nitrogen cycle if you aren't already. Just keep doing water changes, maybe 25-50% every day until you've got low nitrate levels.

Yes, I thoroughly rinsed the sand and everything else before it goes into the tank. And I've been doing 30-50% water changes every day or every other day for the last few weeks.

As for Albinosharkman , Morpheus1967 , TWiG87 , mattgirl ; thank you all for your responses, I really appreciate it!!

Now that I've had a chance to rest and actually think about it the math completely makes sense. Math has never been a strong suit of mine, hahaha!! I think I just overreacted because I've been trying so hard with this tank and I'm excited for it to almost be completely cycled!! I feel much more confident with the better test kit now and will continue to do daily water changes to keep the levels low.

 

[Myyyman]

How is 20 ppm through the roof? That is a perfectly acceptable number after a water change.

I meant when they were 80ppm