Sudden Nitrate spike

[Warnberg]

After a little over two years my tank starting showing signs of nitrate, about 5 ppm... why? I just started doing water changes to reduce it but why after a little over two years would I start to see a nitrate increase?

I thought maybe a dead fish, but all the fish are accounted for....

 

[WarDaddy]

Have you been doing Water changes in the past?

Do you have a deep sand bed (rdsb)?

Do you have a refuge with macro Algae?

Did you have any of the above and recently remove it?

Have you increased your feeding or Bio Load recently?

nitrate is almost the end of the Nitrogen Cycle. Most hobbyists do water changes to export their nitrates. The list above are often used to export nitrates. Macro Algae will turn nitrate into plant growth, the deep sand will house bacteria that will complete the cycle and change Nitrates into nitrogen.

The final option... your accumulation of nitrate has just now finally become detectable... Lots of possibilities, but we need a bit more info

 

[Warnberg]

Have you been doing Water changes in the past?
Yes approx 40 gallons per month

Do you have a deep sand bed (rdsb)?
Yes, I have about a 4 to 6 inch aragonite sand bed

Do you have a refuge with macro Algae?
I have no refugium, but I do have marco in the tank. I do thin it from time to time but none recently.

Did you have any of the above and recently remove it?
No

Have you increased your feeding or Bio Load recently?
I added 5 chromis about 45 to 60 days ago and I added 6 anthias about 20 to 30 days ago.

 

[WarDaddy]

I would say that your problem is related to the addition of 11 fish in the last 2 months...

The bacteria that change Ammonia to Nitrite, and the bacteria that change nitrite to nitrate grow pretty darn fast.

The addition of the fish induced a mini cycle... i bet if you were watching real close you would have see low Ammonia and nitrite levels a few weeks ago.

I bet that if you wait a month the bacteria that consume the nitrate in your deep sand bed will multiply and will be able to keep up with the new load.

Nitrate levels of 5ppm in a FO tank are nothing to be worried about. In fact you could likely take the nitrate to between 20 and 40 ppm without any losses... I would not recommend it, but you would likely survive it.

Sounds like you have a very well balanced and maintained tank. keep it up!

 

[Warnberg]

That's the problem, some of my sps's are not liking it at all. Everything else seems fine and happy, but I'm worried I'm going to loose a few of my corals.

 

[guntercb]

Dave,

I would second Bryan. I bet in another 4 weeks your nitrate will be back down to zero.

I think given the size of your system water changes to reduce the nitrate would not be easy. You need a 120 gallon water change to reduce the nitrates by 1/2. If you corals are hanging in there I would wait a few weeks and see what happen to the NO3 levels. If you need to do something about the Nitrates maybe some Nitrate absorbing media or some kind would work. I believe Randy has written some articles on it.

Good luck,
Chris

 

[mflamb]

Also, continue to harvest algae from the tank. It will encourage it to grow and consume more nitrates.

 

[Warnberg]

Thanks All....

This is what I have been doing to attempt to help. Water changes, 2 40 gallon changes in the last week, increased skimmer (wet skim), cleaned overflows, cut back on the feedings a bit, daily filter sock change rather than every other day.
I will harvest some more macro and hope for the best.