Persistent elevated nitrates - why???

[BAT]

Nerms,

I have a 10g planted tank w one betta and previous snails that died this week. 
 

I had a slight ammonia bump earlier this week and end of last week. I managed w Amquel and more bacteria and 1 water change. Nitrite remained 0. Nitrates were 5-10. 
 

now the ammonia and nitrite Re 0 but the nitrate is 20+
 

At 5p yesterday I did a 40% water change and it is still 20+ this morning. 0 for ammonia and nitrite. 
 

any idea what is going on? Could it be the converted ammonia from previous bump?
 

 

Edited April 2, 2022 by BAT

[Odd Duck]

On 4/2/2022 at 9:56 AM, BAT said:

Nerms,

I have a 10g planted tank w one betta and previous snails that died this week. 
 

I had a slight ammonia bump earlier this week and end of last week. I managed w Amquel and more bacteria and 1 water change. Nitrite remained 0. Nitrates were 5-10. 
 

now the ammonia and nitrite Re 0 but the nitrate is 20+
 

At 5p yesterday I did a 40% water change and it is still 20+ this morning. 0 for ammonia and nitrite. 
 

any idea what is going on? Could it be the converted ammonia from previous bump?
 

 

Yes, it is almost 100% certainty that it’s secondary to the ammonia bump because that’s exactly what happens in a cycled tank.  There was almost certainly a nitrite bump as well, but it was likely so transient that your tests didn’t pick it up.  This is excellent news since it tells me your biofiltration is working well and your BB’s handled the ammonia, then nitrite bumps, quickly and thoroughly.  Now it’s just a matter of either water changing out the nitrates (although I wouldn’t worry too much about that level depending on species or individual fish) or letting your plants gobble up those nitrates.

Your Betta is likely OK as long as he isn’t showing any behavior changes.  If you’re worried about it, just do another 25% water change to drop nitrates below 20.

[BAT]

Thanks @Odd Duck!  Good to hear. Thanks to you and all the nerms who have helped me learn about fishkeeping!!

I decided to do another water change this morning (no gravel vac) bc the betta was acting a little frenetic. He does this when nitrates get to be about 20 so it prompted me to check even though I had just changed. I am a bit over protective bc he had a bad case of fin rot when I had elevated nitrates 20+ for long periods of time. 
 

[Odd Duck]

On 4/2/2022 at 10:18 AM, BAT said:

Thanks @Odd Duck!  Good to hear. Thanks to you and all the nerms who have helped me learn about fishkeeping!!

I decided to do another water change this morning (no gravel vac) bc the betta was acting a little frenetic. He does this when nitrates get to be about 20 so it prompted me to check even though I had just changed. I am a bit over protective bc he had a bad case of fin rot when I had elevated nitrates 20+ for long periods of time. 
 

Good choice!  Especially since you know he’s sensitive to high nitrates.