Is this what you call a mini-cycle?

[Kodgeman]

10 gallon planted, up and running for 17 months. Weekly 25-30% WC and vacuum.

API Master test kit (new one, purchased this month)

January 9: pH 6.6, ammonia 0, nitrites 0, nitrates 20 ppm - pretty much the norm for the last year.

Jan 22: some ammonia, between 0 and 0.25, nitrates ~10 (did 25% WC after)

Jan 26 - 25% WC

Jan 28 - 25% WC, then tested: pH ~6.4, ammonia 1, nitrites 0, nitrates 5

I haven't been testing every week, more like every 3 weeks for the last year, not had much in the way of variation, until now.

One of the neon tetras has dropsy I think - has been looking bigger the last week, tonight I can just about make out scales sticking out.

And I noticed some of the Assassin snails at the top of the tank, right at the water level. They have never done that before, always remain on the gravel. This has got me worried about the water too.

What has changed? Can't think of much. I bought some drift wood on slate and some java fern around the 5th of January from the LFS. Two weeks after I noticed a blue-green colour algae growing on the edge of the slate - not seen that before. I reduced the lighting hours (5 instead of 8 - low light level anyway), increased the Aquaclear 20 flow to max from middle (attempt to increase oxygen in water, hoping to help limit the algae - could be misguided?) and vacuumed up the algae (or what I could see) as it was starting to be visible on the gravel next to the slate. (Not sure if this is what you call blue-green algae, but it is a bright green colour, with a hint of blue. Not stringy, more like a dust that sticks.)

I also bought 4 RCS last weekend. After the first one got eaten I tried to create more hiding places, and disturbed the gravel - stirred up some muck that then settled. I have vacuumed during water changes, but there are still some patches on plant leaves and annubius roots - as if I haven't dusted.

I'll keep changing the water and testing - not sure why the pH would have dropped. Pretty sure of my testing (have worked in labs)... hoping this is a short term thing. Do mini-cycles last long??? Not looking good for the neon, and the RCS all ended up being food...

Thanks for any insight folks, I am hoping this all clears ups quickly, and is just a blip. Not sure what I have done, but perhaps this is just to be expected with a small tank - something gets a little out of shape, and the affect is bigger than in a bigger tank?

[Cliff]

I don't think mini cycles last too long depending on what caused them

Most times it can be a combination of a few things

You stated one of your tetras has dropy, did you add any meds to treat it? Sometimes meds, like certain anti-bacterial meds can kill off some of your BB in your filter causing a mini-cycle.

Also, did you remove a lot od algae from the tank. Alga can really help to keep your your water parameters in check. If you have a lot, it can actually become a part of your tank's filtration. If that was the case here, it will take some time for a little more BB to grow in your filter to make up for the removed algae, causing a short lived mini-cycle

Or, have you cleaned your filter lately and if yes, how ?

Just a few ideas to think about, I hope it helps

[Kodgeman]

Thanks for the reponse, Cliff.

No meds added & filter sponge rinsed out in tank water when I change water.

I did give the tank a bit more of a clean than usual when I noticed the new looking algae - timewise that is close to the start of this. I don`t mind the regular stuff that grows slowly on the glass at the back and one side of the tank (where it is brightest because the lamp is off centre). But when I tried to vacuum up the new-looking stuff I also scraped quite a bit of the regular stuff off too. This clouded the tank a little until I turned the filter on again and it had run for half an hour. Perhaps this was the trigger...

[Kodgeman]

Another 30% water change tonight, ammonia at 2.0, nitrates <5 (closer to 0). At what point do I really start worrying about the fish? I know they must be stressed somewhat, can't see anything in their behaviour.

[KatzeSlaugen]

you should be worrying now. ammonia at 2 is bad for them. youll want to do water changes to get it down to under .5.

have you checked to see if your tests are accurate? test strips go bad if exposed to humidity, and liquid tests expire, or show bad results if the tubes arent cleaned really well

[Cliff]

Is there any way you could have your LFS test you ammonia for you ?

Might be a good idea to have your readings verified just in case you current test kit is not giving you accurate results