My nitrates dropped...

[Geoluk]

I set up my 30g tank 3 weeks ago. I was advised to use a hardy fish as an ammonia source so I got a young bn pleco 12 days later. Although I learned afterwards that it's a bit controversial he seems to be well with good energy and appetite. Using a Sera liquid test kit 5 days ago the results showed 0 ammonia, 1mg/l nitrites and around 25mg/l nitrates. But the last 3 days I've been taking 0 ammonia and nitrites and probably no nitrates (indication colour is deep yellow). I have no live plants and I made no water changes. I feed my pleco every second day with small amount of sera wels-chips and the rest he feeds on the little algae that has grown. I use a canister filter Eheim 2213 classic with sera Siporax bio filter media, 1 blue Eheim sponge, some activated carbon and Eheim green fiber. What is the cause of nitrate drop?? Could it be too soon to tell? Is it possible that some denitrifying mechanism is going on? Should I correct something? I'm looking forward on your response cause I found almost no info about my situation on the internet

 

[FishGuest5123]

Hmmm. No water changes done. Odd. Can you get some bottled bacteria like Safe Start+ and see if it kicks things back into gear? Just don’t use Seachem Prime for 24 hours after adding the bacteria or it will destroy it. After 24 hours it’s fine to use. I’d remove the charcoal for now too.

 

[seangee]

Are you using a liquid (e.g. API) test? Sometimes you get a false negative if you don't agitate the reagents enough.

 

[Metalhead88]

Make sure you're doing the test correctly.

Nitrates should not go down without a water change or plants removing it.

 

[Fishmanic]

Do you have plants in your tank? Plants can soak up some nitrates... especially floating plants like duckweed.