Nitrite spike in established aquarium

[doppelganger]

Has anyone encountered a nitrite spike in an established aquarium? I've been running my heavily planted 125 for over 2 years and I noticed a nitrite spike. None of the fish seemed bothered by it but I've been changing water quite frequently.  Also did an ammonia test and got 0 out of it. I figured it might be waste building up so I vacuumed a bit, cleaned  out the filter, and replaced some of the bio media as well just incase since I haven't changed it since I started. Still getting some nitrites steadily rising. 

 

Anyone else ever experience this? Do you change your bio media often? Any ideas on if it was some sort of die off of bacteria, how long it will take to come back to and balance out in an established setup?

[HH Morant]

Changing the biomedia is a bad idea, especially in response to a nitrite spike. When you take the old media out, you remove bacteria that was converting the nitrite to nitrate, making the problem worse.

Edited April 11, 2022 by HH Morant

[doppelganger]

I changed out maybe like 10% of the bio media and crammed extra I there. 

[Wrencher_Scott]

Yes, I would suspect something rotting in the tank like a dead fish or something. Also I would upgrade the filter to its best possible performance to handle this kind of load in the future. 

I seriously doubt it's BB die off, more likely not enough to begin with. You didn't say what media you use but foam like this is awesome media. The stuff like matrix, ceramic and lava rock suck, all the little pores in it plug up in no time then you have a bunch of basically smooth little rocks for media. Not good.

 

Edited April 11, 2022 by Wrencher_Scott

[doppelganger]

On 4/11/2022 at 11:38 AM, Wrencher_Scott said:

Yes, I would suspect something rotting in the tank like a dead fish or something. Also I would upgrade the filter to its best possible performance to handle this kind of load in the future. 

I seriously doubt it's BB die off, more likely not enough to begin with. You didn't say what media you use but foam like this is awesome media. The stuff like matrix, ceramic and lava rock suck, all the little pores in it plug up in no time then you have a bunch of basically smooth little rocks for media. Not good.

 

It's an fx6 with a mix of different stuff like ehiem substrat etc. Yeah I'm thinking it's probably clogged which is why I switched out a small portion of it. 

[modified lung]

On 4/11/2022 at 12:00 PM, doppelganger said:

It's an fx6 with a mix of different stuff like ehiem substrat etc. Yeah I'm thinking it's probably clogged which is why I switched out a small portion of it. 

Clogging could be the problem. Media like ehiem substrate isn't the best for canister filters unless you're doing regular backflushes (reversing the pump flow and dumping the flush water).