High Nitrate Levels

[terry100]

Hi, I have an Aqua One AR980 215 litre tank that has been running since the end of December 2014. I am now experiencing high nitrate levels. I use an API freshwater master test kit, which is giving readings between 40-80, I find it hard to tell the difference between the two colours. The levels began rising back in April. My current reading is

Ammonia 0

Nitrite 0

Nitrate 40-80

In the tank is:

1 platy

approx 25 platy fry of assorted ages

9 neon tetras

2 bristlenose plecos

1 zebra loach

7 live plants

I do weekly water changes of 25%. I always add Cycle and used to use Nutrafin Aqua + as well but have recently swapped the Aqua + to using Prime (in an attempt to reduce the nitrates). I also purchased a nitrate filter pad about a month ago but so far nothing seems to be helping reduce the level. The temp sits around 26-27 degrees. Also have a UV purifier that runs 24 hours a day and an additional airstone that runs 24 hours. I feed once a day, a mixture of dry flake food and sinking pellets, with frozen shrimp/blood worms as treats twice a week. I feed enough food that gets consumed within a minute. I do use spirulina sinking tablets for the plecos but only give one tablet every second day.

A couple of weeks ago I lost an adult platy and now have a sick tetra (erratic swimming and darting yesterday, today alive but floating). Could these be due to the high nitrate levels and does anyone have any ideas on how to reduce them. I was thinking of trying a Nitra Zorb pouch next? Thanks

[camtang]

Maybe increase the volume of water you remove or do it more often?

Have you tested the nitrate from your tap?

Also, API nitrate tests are notorious for false results.

[terry100]

Hi, I just tested our tap water (we live rurally so our water is sourced from a spring), the reading came back as 10-20. What nitrate testing kit would you recommend? Thanks

[alexyay]

I personally prefer Seachem for their Nitrate/Nitrite test kit. My API Nitrate kit was reading 2x the actual result, leading me to believe I had a Nitrate problem that I didn't actually have.

The symptoms definitely could be due to high Nitrates, but could also be due to other issues such as Parasites or issues with pH. Prime will help reduce the toxicity of the Nitrates but won't help to reduce them. I'd be a little bit careful with the Nitrazorb as it also takes in Ammonia and Nitrite, and may interrupt your tank's cycle.

Typically I'd recommend testing your kit simply by doing a 50% water change. Based on the assumption that the water is around 0ppm Nitrates, the tank water's Nitrates should be roughly halved. Unfortunately it's a bit difficult with tap water Nitrates of 10-20ppm as fish such as Neons and Fry may struggle with Nitrates above 20ppm. It may be worth considering running your water in a barrel with Nitrazorb or an Aquaponics system before introducing it to your tank, as IME a lot of tanks go up about 20ppm during the week, and you'll likely to continue to have Nitrate issues with high tap Nitrates.

Adding plants can help in the long-term with Nitrate production - emersed plants such as Peace Lilies, Pothos and Syngonium or even edible plants such as Mint will help take up the Nitrates (it may take a little while for plants to become established). Fast growing submerged plants like Hygrophila polysperma, Ambulia, Indian Fern etc are all good for Nitrate consumption too.

(Just as a side-note, I'd recommend adding more loaches to make a group of 6+, however I'd understand that you won't want to do this while Nitrates are high!)