Aquarium not cycled after 2 months

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AKLB

Aquarium Advice Apprentice
Joined
Mar 29, 2017
Messages
36
Location
United Kingdom
Hello,

I've been fishlessly cycling my planted 200l/55g aquarium since the start of June using ammonia. Within the first few weeks my ammonia levels were starting to drop off and I was beginning to see nitrites and nitrates, and apart from a brief period when my nitrites stopped reducing, everything seemed okay.

Around a week ago it seemed like my cycle was nearly finished as 4ppm of ammonia was being reduced to 0.25ppm and all nitrites were disappearing within 24 hours. However, since then my ammonia has suddenly stopped converting into nitrites and does not reduce at all from 4ppm for several days. As I am writing this post my ammonia is at 4ppm, 4 days after redosing.

What can I do to finish this cycle? I've looked online, and some people are saying I could use Tetra Safestart and stock a small group of fish to finish the cycle. What do you think about this?

Over 2 months seems like a very long time for my aquarium to not be anywhere near finishing.

Hope you can help,
Adam
 
A couple weeks ago, I was under the impression you weren’t supposed to do water changes unless nitrites spike. I’m guessing that’s wrong?
 
Imo water changes would be fine and quite often done to lower readings down from ‘off-the-chart’ to within test kit range. Also useful where ph drops too low (and useful elements have been deleted that bacteria need). As well there may be other elements used, so sometimes a water change kick-starts a stalled cycle.

Copied in text:

1 ppm ammonia --> 2.7 ppm nitrite --> 3.6 ppm nitrate.

For every gram of ammonia oxidised into nitrate 4.8 grams of oxygen is used, 7.14 grams of calcium carbonate is used (thus why pH crash can occur in tanks with to little buffering capacity).
 
Well it’s been a little over a month since I made this post, and my tank still doesn’t even seem to be nearly cycled. Ammonia is still taking ages to come down.

Any more help?
 
So ammonia was coming down but now isn’t? What are all your chem readings? And water changes made no difference?

Beginning to sound like a stalled cycle. I assume tap water hasn’t changed and the water conditioner you are using is just getting dosed as per bottle? Over-dosing can sometimes slow down cycling.
 
Ammonia is around 4ppm (redosed it to around 4ppm 3 days ago after a water change). Nitrite is around 0ppm. Nitrate is very high, somewhere between 80ppm and 160ppm. pH is around 8.4.

The last time I performed a water change was 3 days ago, and I have been doing it every week or so since this post was created.

My tap water hasn’t changed. I may have been slightly overdosing the water conditioner after a water change as the recommended dosage is so small, but this shouldn’t have been overdosed by a crazy amount.

Not sure if this helps at all, but the aquarium is planted with java fern, anubias, cryptocorynes, dwarf floating lettuce and some marimo moss balls, which I fertilise with Seachem Flourish Excel according to its instructions. Maybe planting some more could help? I tried adding some vallisneria a while ago but they all died fairly quickly.

The water conditioner is Seachem Prime. I also have an airstone bubbling away as I read that it could help speed up the cycle.

Just out of interest, what do you think about products aimed at speeding up a cycle, such as Tetra Safestart?

Sorry for the long reply, I’m just trying to list everything I can about the tank in case something I haven’t thought of could be stopping my cycle.
 
You could try the bacteria in a bottle. Products can be hit or miss but rarely cause issues. Go with a leading brand from a shop that stored it well (ie not in some shed out back over summer). I’ve used and thought helpful.

I wouldn’t stock fish yet until have an idea of cause.

Is ammonia reducing but just very slowly?

I assuming tap water is 0 for ammonia and nitrates. And after you do a water change, that nitrates drop and then rise again. If the case, it sounds more a mini-cycle where nitrates are being produced but the ammonia to nitrite converting bugs have taken a hit to the population and are re-building. Just a thought to check. Nitrite at 0 says that is fine.

In a young tank this could be from any meds, liquid carbon, algal, etc treatments or from too much cleaning of filter. It could also be from really gunked up filter (bugs get covered) or filter too small but this tends to be from goldfish kept in very small tanks (filter can’t handle bioload - doesn’t sound a problem here).

That’s all I can think of. Might get some other thoughts from others. The water conditioner and plants all sound fine. Ph sounds fine.

One very last thought is I assume the test kit is working fine. Generally these hobby test kits are fine for what we do but can give major errors if eg bottle cap left off. It doesn’t sound the case but posting all I can think of / heard of. I’ve found the test kits pretty good myself.
 
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Nitrates are going to be high if your fertilizing. Might just slow down on water changes. Leave the ammonia where it's at, wait for nitrites. If no nitrites but your nitrates keep growing and your ammonia drops then I'd say you're cycled. If cycled do large water changes until you are around 10 ppm nitrates then add fish.
 
My ammonia is reducing, but very slowly.

According to my water suppliers website, the tap water ammonia levels are 0.014ppm and the nitrate levels are 13.96ppm.

Test kit should be working fine, I’m using API Freshwater Master Test Kit. I had to buy some more ammonia tests (same brand) as I ran out, and both tests were giving the same results.

I’ll try and leave everything to see if ammonia eventually drops to 0 and I still have no nitrites. If this doesn’t work, I’ll probably try a bacteria product.

Thanks for all your help [emoji4]
 
Hi again everyone,

My ammonia has come down to 0ppm after 5 days, and nitrite is still at 0ppm. What do you think?
 
I think you are cycled but maybe not a lot of BB growth?? That's why it's taking so long to convert the ammonia?
 
Personally, I would. But Im also not against fish in cycles. If you do add fish go lightly at first. Regularly test the water. If it isn't cycled be prepared to do frequent water changes for a while until it is cycled.

IME, and by no means is this proven science, I seem to cycle tanks quicker with fish and plants. I've used strictly fish food to cycle a tank and it took me about 8 weeks. Ive used feeder fish in the past to cycle my tanks.

The quickest I've ever cycled a tank was 3 weeks and by accident. I was brand new at this, threw in 15 fish at once in a 29g tank, had a bacteria bloom within 18 hours and ich on every fish within 48 hours. Long story short, I was doing daily 25% water changes and by the time I got everything under control and gained some knowledge, I was cycled in 3 weeks. Lol. I don't recommend this.
 
LOL I would recommend the first part of light stocking etc. as mentioned by King Fisher - not the last part!

As you are monitoring now often, it is likely you are, as mentioned cycled but with a small amount of BB, and will be testing to make sure all is well for keeping fish.

For a finish up fish-in cycle, just to make sure to not get cocky, keep monitoring until you feel comfortable with a stable series of tests over the course of a few weeks.
 
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