When ammonia drops but not nitrite and other cycling issues

[enricosonic]

I’m several weeks into my fish-less cycle. A 75 gallon planted tank. My ammonia has recently dropped from 3-4 ppm to between 0-.25 ppm and my nitrite remains between the 2.0-5.0 API color chart, the latter reading has not changed for a couple of weeks.

Should I start performing water changes?

 

[enricosonic]

Nitrite is spot on 2.0 ppm

 

[Rocky998]

No, don't do water changes... It will take a bit for the nitrAtes to show up and rid of the nitrItes... My cycle took a while for this to happen, just wait for nitrItes to fall to under 0.50 and then add another dose of ammonia... Once the ammonia and nitrites go away in 24hrs your cycle is complete. THEN do a massive water change

 

[Essjay]

With a fishless cycle, you normally only do one water change right at the end.
However, there is one circumstance where water changes help. If tap water has low KH it can get used up and the pH drops. Where this happens, water changes replenish the KH and reset pH back to tap water level.
Has your pH dropped?

How close to 5 ppm is nitrite? If it is 5, it could be well over 5 ppm but it would still show the 5 ppm colour.

 

[enricosonic]

With a fishless cycle, you normally only do one water change right at the end.
However, there is one circumstance where water changes help. If tap water has low KH it can get used up and the pH drops. Where this happens, water changes replenish the KH and reset pH back to tap water level.
Has your pH dropped?

How close to 5 ppm is nitrite? If it is 5, it could be well over 5 ppm but it would still show the 5 ppm colour.

Yes my pH dropped, it is in the 6.0-6.2 range. I get the API chart range is limited, but my eyes see nitrite at between 2.0-5.0.

What do you make of it:

 

[Rocky998]

Its definitely less than 5 from what I see...

 

[Essjay]

It could be anything between 2 and 5 ppm.

But if your pH has dropped, the cycle could have stalled. What was the pH when you started, higher? Do you know your KH level in your tap water (a water provider will call it alkalinity if they list it). KH is inorganic carbon which the bacteria need to grow and if that's dropped the cycle could slow down to very slow.
If your pH has dropped a lot, a large water change would probably help - and keep an eye on the pH for the rest of the cycle. Dose ammonia to 3 ppm after a water change.

 

[enricosonic]

I'm seeing things at this point

Its definitely less than 5 from what I see...

I tend to agree but I've been seeing too many shades of purple for too long.

 

[Rocky998]

I'm seeing things at this point

I tend to agree but I've been seeing too many shades of purple for too long.

Yah, it can be confusing.

 

[enricosonic]

It could be anything between 2 and 5 ppm.

But if your pH has dropped, the cycle could have stalled. What was the pH when you started, higher? Do you know your KH level in your tap water (a water provider will call it alkalinity if they list it). KH is inorganic carbon which the bacteria need to grow and if that's dropped the cycle could slow down to very slow.
If your pH has dropped a lot, a large water change would probably help - and keep an eye on the pH for the rest of the cycle. Dose ammonia to 3 ppm after a water change.

From the tap, my water is approx. 7.0. So yes a drop to low 6 range. Maybe worth noting, there are 3 large pieces of driftwood in there. Don't technically know the KH, getting wildly different info online and it is a holiday so I can't make a phone call to the water provider. I can break out the Python a do a 50% water change if you recommend it.

EDIT: Water change then re-dosing ammonia now

 

[enricosonic]

Dosed ammonia about 30 minutes ago, not sure how long before this reading is accurate.

 

[Rocky998]

Dosed ammonia about 30 minutes ago, not sure how long before this reading is accurate.

View attachment 155145

Usually the results come in, in about 5 minutes but I wait 10 just to be sure. If you read the manual it tells you how long each one takes and how much of what to add and how long to shake the liquids.

 

[enricosonic]

Usually the results come in, in about 5 minutes but I wait 10 just to be sure. If you read the manual it tells you how long each one takes and how much of what to add and how long to shake the liquids.

I get that part, I meant how long after adding ammonia to the tank will I get an accurate reading on the new ammonia level, if the makes sense.

 

[Rocky998]

Ohhhh ok. Sorry... Usually a bit after 30 minutes of having the ammonia run through the tank it registers accurately...

I get that part, I meant how long after adding ammonia to the tank will I get an accurate reading on the new ammonia level, if the makes sense.

 

[mbsqw1d]

You'll probably end up running an acidic tank where the latter stages of the nitrogen cycle aren't an issue. Ammonia exists as less toxic (almost harmless) ammonium, and if you're planted and not overstocked, everything will take care if itself.
You'll need to keep a close eye on your pH during the early stages until you get a feel for how its running.

Or, and depending what fish you want to keep, you might want to look into buffering your water by adding salts that raise the KH. This will ensure growth of nitrosomonas bacteria and keep the cycle stable.