Fish-in cycle, news too good?

[Linwood]

Short version: Can a 45g tank cycle in 8 days with a peak of no more than 0.5 Ammonia?

Longer version:

45 gal lightly planted freshwater tank, started 6/17 with new filters, no prior media, but "Smartstart Complete" added. Three fish (Raphael Catfish and 2 x Serpae Tetra) added 6/19 with a few shrimp.

Water is high ph (peaked to 8.6, found out tap water is very high ph here, didn't check before filling tank). Brought it slowly down to 8 so that during cycle it is not quite so bad.

By day 6 started seeing 0.25 Ammonia; added 3 more tetra on day 8 (still 0.25).

By day 11 Ammonia went to 0.50, and first time nitrites appeared at 0.25, then Ammonia went down to 0.25 the next day, and vanished the 3rd (today) which is day 14 overall.

But Nitrites also vanished today, and so far no detectable Nitrates. So basically this morning I had all zero's, but if what I think the conversion ratio is (about 4:1), it could be the nitrates are just below the accuracy of the test (API Master Freshwater Test kit).

But... from trace to gone, never getting above 0.5 in 8 days?

Is that reasonable? Did that "Smartstart complete" work that well?

Or is something else going on?

More fish? I wanted a minimal number so it was a slow, low-peak cycle; time to add more and see if Ammonia stays low/zero?


Other details: Hardness 3 (per LFS, not sure what test), 78 degrees, Fluval 306 filter with default media, no water changes about 4 gallons added to top off, about 6 small plants, substrate is grave + 1 bag of Eco-Complete.

 

[BBradbury]

Fish In Tank Cycling

Hello Lin...

With enough fish to provide a steady source of ammonia, all you need to do is test the water daily for traces of ammonia or nitrite. If you have a positive test you remove and replace roughly a quarter of the water with pure, treated tap water. When several daily tests show no traces of either of the above toxins, the tank is cycled. It routinely takes a month for the nitrogen cycle to run it's course, but maybe you've found a faster way to get it done.

Good for you,

B

 

[Mebbid]

It's possible but I would look at the amethod of the nitrate test. They are commonly done improperly and that gives a 0 reading. Are you following the directions to the letter including times shaking of the bottle and vial?

If memory serves 1ppm of ammonia turns into 2.8ppm of nitrate or something along those lines.

 

[Linwood]

It's possible but I would look at the amethod of the nitrate test. They are commonly done improperly and that gives a 0 reading. Are you following the directions to the letter including times shaking of the bottle and vial?

If memory serves 1ppm of ammonia turns into 2.8ppm of nitrate or something along those lines.

Yes, the test kit had that in bold, large print so am doing that faithfully.

But it's minimum reading (per the card) is 5ppm, so if the highest combined readings of ammonium + nitrite (which is a slightly lower conversion I think) were 0.5 and 0.25, it's very possible that if they converted to Nitrate (and where else could they have gone) it would be under 5ppm.

So the readings are not inconsistent, so much as a surprise. With no prior BB on media, just the smartstart, I am surprised the ammonia did not peak higher. But maybe the LFS's advice on number of fish was spot on?

 

[Linwood]

When is a cycle like a yo-yo instead?

So after reaching zero ammonia, now it went back up, first 0.25 then 0.5, with nitrites going up slightly (0.25), and still no nitrates.

Looks like it's a very slow, tentative cycle?

 

[fireman731]

I used tetra safe start in my tanks and they have all cycled very quickly and remained stable


Sent from my iPhone using Aquarium Advice

 

[Linwood]

Well, I remain confused.

Nitrites rose slowly to 2ppm, stayed there about 5 days, dropped to 1 for 3 days, and crashed now to zero. Clear zero, no hint.

And Ammonia which had been a steady 0.25 now is up to 0.5.

No idea what's going on. Hoping that nitrites stay down, and the ammonia is a short term thing and it's actually done.

Nitrates are up a bit, more than 5, less than 10.

Is this kind of random variation normal?

 

[PB_Smith]

When is a cycle like a yo-yo instead?

when the tank isn't fully cycled.
I never consider a tank cycled until it has been running for 4-6 weeks, regardless of what the water tests tell me.
if the levels remain so low then yes it will be a long process to be fully cycled.
I would refrain from doing water changes at any sign of ammonia/nitrite, but maybe let the levels get up a bit higher.
If you are consistently removing the food source for the bacteria, how can they quickly populate your tank?
I know I'm getting disapproving frowns and shaking heads as folks read this, but if you never allow the levels to rise to a certain point, the tank will be perpetually cycling until you reach your final stocking limit.


or you could just go with some other folks recommendations and do 50% water changes every three days.

 

[Mebbid]

If the tank hovers at .25 ppm of ammonia then there is more than enough food for bacteria to reproduce. I definitely wouldn't water change at .25 ppm but if you keep it at around that level then its a safe number for the fish to stay while providing ample supply of food for the bacteria.

 

[Linwood]

I've only done one water change when the nitrites initially spiked really high, and that was only a quarter. Other than that, no changes, no filter change/clean, just waiting.

What's surprising to me is that the nitrites really crashed, they were steady a long time, then a slight decline one day, and zero the next. Really zero, no ambiguity in the color.

But on that same day ammonia went up from 0.25 to 0.5.

I guess a bit more time will tell.

But... no water changes. I only did the one because it was such a sharp nitrite spike and I wanted to take the edge off, as it were, for the tank. But it made almost no difference in reading the next day, it naturally came down a bit then stayed constant over a week.

 

[PB_Smith]

I've only done one water change when the nitrites initially spiked really high, and that was only a quarter. Other than that, no changes, no filter change/clean, just waiting.

What's surprising to me is that the nitrites really crashed, they were steady a long time, then a slight decline one day, and zero the next. Really zero, no ambiguity in the color.

But on that same day ammonia went up from 0.25 to 0.5.

I guess a bit more time will tell.

But... no water changes. I only did the one because it was such a sharp nitrite spike and I wanted to take the edge off, as it were, for the tank. But it made almost no difference in reading the next day, it naturally came down a bit then stayed constant over a week.

Actually with the relatively small bioload, the climb up then sudden drop in readings makes perfect sense. Once the bacteria are established, the can do pretty fast work. That is one reason to maintain a minimum amount of ammonia while cycling, so the BB can hit that population plateau where they can almost immediately deal with waste. I think that is what you saw with the readings for nitrite, the bacteria just hit a high enough population to quickly break down the waste present.

 

[Linwood]

I think that is what you saw with the readings for nitrite, the bacteria just hit a high enough population to quickly break down the waste present.

That one I get. What I don't get is the same-time increase in ammonia. I would have expected that bacteria to be getting more and more efficient over time.

Maybe I fed a bit more heavily or something the night before, so another day or three will likely ttell.

 

[Linwood]

FINALLY, I think it's cycled. Ammonia and nitrites zero, and nitrates slowly rising.

I know every tank is different, but I know I had trouble finding indications of how long this takes, so for whatever it is worth, here's how mine went over time.

Total time right at a month. The clear rise/fall was in nitrites, ammonia just hung in there for quite a long time, with one period of zero in the middle. I took a water sample in and the LFS also got a zero reading today as well.

I'm not doing a water change yet, going to give it a few days and make sure it stays zero.

Anyway, thanks for the advice.