Nitrate Elevation

[priebjm]

I have a 55g FOWLR tank. My nitrate level has been 5-10ppm for the 10 months I have been running. My last test at 10 was 12/22. Ammonia and Nitrite are 0. Yesterday and today the nitrates are roughly 30.

Yesterday this is what I did differently:
Added 2 Peppermint Shrimp and 6 snails which I would assume would not effect nitrates. What may is that I found out that the life I was seeing on my LR was Aiptasia. I killed them with Elimi-Aiptas. Would the die off cause a nitrate spike so quickly ?

I am also using a Penguin 330 HOB filter and it was suggested to me that I remove the bio-wheels if I was going to continue using the filter for mechanical filteration. The suggestion was to only remove one wheel at a time to give the tank time to adjust. Could removing one wheel spike the nitrates ?

At what point should I look to lower the nitrates or will they lower on their own ?

Thanks for any advice

[kaybee]

Bio-wheels on a marine system may perform as a 'nitrate factory', but if they've been on for the entire 10 months of operation, that doesn't explain the abrupt +20ppm nitrate spike.

Seems like the only recent 'change' was the use of Elimi-Aiptas, I wonder if something in the ingredients could be a factor.

What type of fish are in this system (species, size and quantity), approximately how much live rock is in your FOWLR tank and if you utilize a deep sand bed, how deep is it?

[priebjm]

Thanks for the response
1-Maroon Clown
1-Royal Gramma
1-Coral Beauty
1-Green Chromis

All approx 2"
Approx 30# live rock (realize not enough for 55g)

Substrate is crushed coral. I realize now this was not a good choice, but it has been in all 10 months.

[kaybee]

You could add more live rock.

Crushed coral traps detritus more than fine-grain sand and its use could have a nitrate-accumulation effect the longer it is used. Additionally, your fish may have grown since you have gotten them and are producing more ammonia (which is being converted to nitrate) than previously.

Again, these factors should have had gradual nitrate elevation effect rather than a sudden jump in just a matter of days.

Have you been using the same test kit all along and did you double check the results? What brand are you using?

[priebjm]

I have always used the API NO3 test kit.
The one thing that is making me second guess the results is that I have read that if you don't follow the instructions specifically the readings may be incorrect. I have only recently begun to be more concious of the process time.

Is it possible in your mind that the dead Aiptasia could cause a sudden rise ?

[Halelorf]

If you killed enough aptasia then yes it could spike your chemstry levels. I would do a larger than average water change and keep a close eye on the levels.