Nitrites In Fishless Cycle

[lou10579]

Hi guys, I'm new to posting on these boards but have been reading for a few months now.

I'm not actually new to the hobby. I did freshwater years ago, switched to salt for several years and just went back to fresh at the beginning of the month... which brings me to my question.

I'm doing a fishless cycle and I'm curious as to why I haven't seen nitrites on my tests yet. Below is a summary of equipment and things done so far:

Tank is a 20H
65W 6700K lighting
Water is RO from Walmart
20 lbs of Flourite and 5 lbs gravel
API Freshwater Master Test Kit
Aquaclear 70 power filter
DIY CO2 injection (yeast)
7 live plants
Temp 84
PH approx 7.3 - 7.4
Ammonia 4 ppm
Trites 0
Trates 0
6 dKH
No water changes yet.
1 capful of Kent Freshwater added 4 days ago.

I loaded the tank up on Sept 6 with equipment and water. On the 7th I added enough ammonia to bring to 5 ppm and have been bringing it back up periodically since. Nine (going on ten now) days later though, no nitrites. I realize I may not get a 5 or 6 day cycle doing this, but I was confident I'd see at least .25 ppm nitrites by now. Any thoughts?

Thanks in advance for your feedback and for all of your posts on these boards. It's amazing how much one can learn just perusing them.

 

[Mr Bliss]

Since you have plenty of light and CO2 injection, I suspect your plants may be gobbling up the ammonia. If the plants get growing fast, you may never be able to follow the progress of the filter cycle because the plants constantly consume ammonia, nitrite and nitrate. If that happens, I'd just wing it: wait X weeks and start gradually adding fish.

Some planted tank hobbyists skip the entire cycling phase and just plop the fish in as soon as the water has cleared, but I'm not going to recommend that since I believe it's better to err on the side of caution when the well-being of living animals is involved.

edit: the above is particularly likely if your plants include Hygrophila. Hygrophilas are famous for taking up and storing ammonia at a rapid rate.

 

[Miss Wiggle]

yup the process discussed above is called 'silent cycling'. it's where the tank is planted so heavily that the plants absorb all the excess ammonia that you'd normally get in the first few weeks of a fish-in cycle, meaning you add fish straight away and the filter will cycle to handle some of the waste, but the remainder will be dealt with by the plants.

it does however take quite a lot of plants to achieve this, best way for us to tell if this is likely for you is to post up a picture of your tank and while we can't say conclusively from that we will be able to make an educated guess.

another possibility to be considered is a faulty test kit. doesn't happen all that often but no manufacturing process is perfect, you'll always get the occasional duff one. so get a sample of your water, run a series of tests and write down the numbers, take the remainder of the water from the same sample to your lfs and get them to test it, compare the results and you'll immediately tell if there's any fault there in the recording equipment.

 

[lou10579]

Intriguing. I wasn't aware of the "silent cycle." I'm going to have my LFS test my water. If they don't detect nitrites, I'm going to wait a few days and see what happens.

Thanks for the responses.

 

[OldMan47]

If you are successfully keeping an ammonia concentration in the tank, the cycle will produce nitrites in your tank. The fact that some of the ammonia is absorbed by plants will not block the action of bacteria in your filters. As long as you have ammonia present you are in a fishless cycle that has a good chance of success. If your plants are reducing ammonia to none detectable in just a few hours the story would be different but that is not what you posted. The nitrite spike can easily take 3 weeks to happen so don't jump the gun and put fish into your uncycled tank yet.

 

[waterdrop]

Yes, good oldman, I was going to say this earlier. Lou10579 has only begun the fishless cycle a week and a half ago. In my own case and the majority of people I've helped in the forum here, its taken more like 21 days, ie. the 3 weeks you mention, before the ammonia is dropping quickly and the nitrites are spiking. In my own case the fishless cycle took almost exactly 3 months total, but I had some pH crashes that slowed things down a bit.

I agree that the silent cycle may be playing a role here and should be watched, but more likely its just time that's needed.

~~waterdrop~~

 

[lou10579]

Tested again last night and the nitrites finally appeared. It looked to have been somewhere between 0 and .25 ppm. This morning it tested at a solid .25. I'm on my way!

 

[waterdrop]

congrats on reaching another fishless cycling milestone

 

[lou10579]

Whoa, nitrites are maxed out on the chart today! That was fast!

 

[OldMan47]

You get about 2.7 nitrites for each ammonia ppm that is converted. If you had 5 ammonia, that is about 13 to 14 ppm of nitrites. Your plants take up some so you are only converting the difference that they don't use. The fact that the nitrite spike is so high is not a problem. If you lose track of the nitrites or become impatient, you can do a large water change and get nitrites back to where they can be measured. It will not harm your cycle to do so and for many people, it is better if they can see what is happening.

 

[lou10579]

Thanks for the tip Oldman. Since the ammonia first dropped to 0, two days ago, I've been adding enough to bring it back to 2ppm daily... and it's been dropping back to 0 daily..

Just have to wait on the nitrites now...

 

[waterdrop]

When the nitrites start dropping to zero in under 24 hours you can ease upward from 2ppm to 5ppm on the daily ammonia add so that by the finish you'll have larger bacterial colonies.

The robust test is when 5ppm of ammonia add drops to zero ammonia and zero nitrite in under 12 hours. Even after passing that test it is good to watch it do that for about a week, or whenever the next weekend arrives and you wish to do the big water change and add the first batch of fish. You have to be ready on the initial fish choices by that point.

~~waterdrop~~