Cannot get rid of nitrates while cycling

[follicle]

Hello all,

I've been cycling my 9 gal planted tank and just can't get the nitrates to disappear. It's been cycling for more than a month now. All else is going good. PH is good. Ammonium and nitrites have disappeared. Plant growth has been great. But for the past two weeks or so, nitrates are reading consistently at 5.0 ppm. This is a fishless cycle. Plants only.

I know water changes during cycling seem to be debatable topic, but I went ahead and performed two (~40% water) in the course of one week with no change.

Any thoughts on what might be occurring? Should I keep waiting it out?

Thanks in advance!

 

[Aiken Drum]

Nitrate is the end product of the nitrogen cycle. In normal circumstances the only way to remove nitrate is water changes.

 

[ColdKoi]

You can wait as long as you like. It’s only going to rise! Lol

Like Aiken stated, nitrates are the end result of the nitrogen cycle. Typical aquariums will never reach a true cycle where there’s enough anaerobic bacteria and plants to use up the nitrate as it is being produced. Nearly every aquarium requires regular water changes to control nitrate levels

That being said, in a planted tank you generally want to keep the nitrates up a bit to allow the plants to feed off of it rather than solely fertilizers and additives.

Your tank is cycled and it’s time to add your fish and enjoy. Just keep an eye on the ammonia levels for the first week or so to make sure they don’t spike. If you introduce more fish waste than the amount of ammonia you’ve been dosing in your fish less cycle there may not be enough bacteria right away to control the ammonia levels. Again easily controlled by reduced feeding or water changes

 

[follicle]

Your tank is cycled and it’s time to add your fish and enjoy. Just keep an eye on the ammonia levels for the first week or so to make sure they don’t spike. If you introduce more fish waste than the amount of ammonia you’ve been dosing in your fish less cycle there may not be enough bacteria right away to control the ammonia levels. Again easily controlled by reduced feeding or water changes

Interesting! I've cycled a tank before but always just assumed the nitrates died off. Faulty assumption on my part. I plan on performing weekly water changes. I understand the nitrates might eventually fall a bit but is .5 ppm a safe amount of nitrates to begin introducing fish? Just want to make sure before I slowly start introducing. I'll keep an eye on ammonium and nitrites. Thanks!

 

[ColdKoi]

Nitrates are fairly safe for fish even at higher levels. I’d suggest maybe doing some reading on the subject (Aiken drum has some good write ups).

You’ve got a planted tank. I usually keep my planted tanks at 10-40ppm. Ideally doing the water change when it’s in the 20-40ppm range and doing no more than 50% change to attain ~10-20ppm. These levels are more than safe especially short term and the plants are doing great.

If you try to keep nitrates under 5ppm you’ll be chasing your tail with water changes as well as starving your plants of nutrients (or having to supplement them)

 

[follicle]

Nitrates are fairly safe for fish even at higher levels. I’d suggest maybe doing some reading on the subject (Aiken drum has some good write ups).

You’ve got a planted tank. I usually keep my planted tanks at 10-40ppm. Ideally doing the water change when it’s in the 20-40ppm range and doing no more than 50% change to attain ~10-20ppm. These levels are more than safe especially short term and the plants are doing great.

If you try to keep nitrates under 5ppm you’ll be chasing your tail with water changes as well as starving your plants of nutrients (or having to supplement them)

Excellent! Very informative. Thanks!

 

[Aiken Drum]

How much ammonia have you been dosing? I suspect with the low amount of nitrate you have you arent dosing ammonia and therefore not really doing a fishless cycle. Your tank might have had small amounts of ammonia in it (leaching from substrate, plant die off, maybe chloramine treatment) and thats where your nitrate came from. But thats not enough to cycle a tank.

If you are dosing 2ppm ammonia and 24 hours later you are seeing 0ppm ammonia and nitrite you are cycled.

If you plan on doing a fish in cycle then you can add some fish and start to cycle the tank.