Potassium Nitrate and Nitrate in tank

[kellyboy47]

I'm not sure if I'm posting in the correct thread but does Potassium Nitrate dosing affect Nitrate / Nitrite levels in the aquarium. I dose macro / micro ferts on alternate days of the week with a days rest before a water change but I have been having regular unexplained fish deaths and whether this could be a contributing factor ? Any thoughts would be appreciated

 

[ian_m]

Inorganic nitrate from say potassium nitrate does not raise nitrite levels in a well filtered tank. For inorganic sourced nitrate to start having fish issues you are talking in the 1500ppm levels, many many times the levels you should be dosing at. Due to a pump failure I ran with 350ppm nitrate (and 80ppm phosphate) for a week with no fish or plant issues.

However organic sourced nitrate, not that you can tell the difference or test between inorganic sourced and organic sourced, they are the same, nitrate is nitrate, is the smoking gun that indicates something has gone wrong or tank is not cycled. Ammonia from uncycled tank, new substrate, rotting plants, rotting fish is toxic to fish. This then converted to nitrite, which again is toxic to fish before finally being converted to "harmless" nitrate.

 

[sciencefiction]

Theoretically yes, there is scientific information that elevated nitrate even from inorganic nitrate can raise nitrite level via the process of denitrification. If you have deep substrate, or the filters have nit been cleaned in a while, ir generally low levels of oxygen in the tank, and not enough plant mass/growth, then this is a possibility.

However, this is only a guess and the deaths could be due to thousand other reasons. If you provide more details about the tank and fish, perhaps we can narrow it down.

 

[Sakura83]

Look for death fish, you may miss one.