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High ammonia, low nitrate


blueether

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I haven't done a water change for about 3 weeks as I have been keeping an eye on ammonia / nitrate and todays test the NH3 is at above 2 ppm and NO3- has droped to below 5ppm, close to 0?

6849767651_ba4c831391.jpg

tests by nzbeeman, on Flickr

[EDIT] the NH3 and NO2- are 1/10

This seems odd to me.

There is no planting (a little algae/duckweed) but there is a DSB of 80mm for about 1/3 of the tank (~600mmx400mm).

Filter sponges/wool were cleaned 3 weeks ago, noodles/bioballs not cleaned.

I have replaced the internal pump of the cf1200 with a 3200l/h pump that also drives the chiller, is there too much flow in the filter? I guess there would be ~2000 - 2500 l/h.

Any thoughts?

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If your biological filter had taken a hit, wouldn't that cause ammonia levels to rise, and both nitrite and nitrates to fall? Ie. your tank has started to recycle. I don't see the numbers but is your pH below 6? That can disrupt the nitrogen cycle.

See http://www.oscarfishlover.com/forum/14-tanks-filtration-heating-etc/124216-old-tank-syndrome--tank-recycling-process

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weird.

i would say something has happened,

ow much bio media do you have?

a well established aquarium should not get spikes, but mainly, if your bio media is enough.

i would say your bio media isnt enough, and that it is spiking due to insufficient capacity?

apart from that, dont know what else, food trapped somewhere?

dead fish hidden

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Just the cf1200, it has the media that came with it (ceramic noodles & bioballs) plus another 1.2kg of aquaone ceramic noodles. There is about 25 - 30 l of sand substrate.

Cant see any dead fish, the filter has been running for about 1 year and the tank has been in its current scape for over 3 months.

Will do a water change tomorrow to lower the ammonia...

[EDIT]

What may have changed is that the cyano is dieing off abit but I wouldn't think that it would be enough to raise the ammonia that much and it started to climb before the cyano started to die back

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I suspect the most important thing is that your pH appears to be below 6 on the graph, and that would stop the nitrogen cycle. What is the pH of your source water?

If this is old tank syndrome, the recommendation is to change water daily 10-20%, and to stop if ammonia levels don't start falling to give the bacteria a chance to catch up. At low pH levels ammonia is found more in the non toxic ammonium state which protects the fish.

I was under the impression a DSB is helpful to reduce nitrates only if you have something (worms etc) living in the DSB which is constantly turning it over so that the nitrate rich water reaches the anaerobic bacteria.

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The only thing that has changed in the last 3 weeks is the new pump and washing the sponges :dunno:

Washing the sponges in what - tank water or tap water? My tank pH sits low - maximum 6 (my test chart does not go lower than that) and the one thing guaranteed to cause my tank to recycle is if I wash out more than 2 of my fx5's sponges under tap water. I have no issues when I wash out the media but I will get high ammonia if I wash my sponge's in that way. I find if I only wash out the sponges on only 1 or 2 of the 3 filter baskets with a hose I can manage it, so these days I tend to put the tank water into a bucket and wash them.

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@Graham/Mark: I have read conflicting things about DSB some say you need worms etc others say that the turning over of the DSB introduces too much O2, It did have our native snails that do turn over the sand but the fish keep eating them. There is a 5000 l/p wave maker pointing at the bottom/sand that should help move some water through the DSB

I know that with cold water and a low pH that ammonium/ammonia balance is well in my favour.

"pH appears to be below 6 on the graph, and that would stop the nitrogen cycle" That I didn't know, it is very close to a pH of 6 or below, chart only goes to 6.

@Adrienne: Yes it was in tap water, always done them that way. Maybe it always does a mini cycle after I wash them, just have never tested the tank before

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I would have thought that 2kg of noodles would hold enough bacteria :facepalm:

yes it holds a lot of bacteria but maybe more in the sponges

remember you have a tank running in balance for waste and bacteria

you have tipped the scales on one side which can start a chain reaction

with a rise in ammonia killing off more bacteria

questioning the way you cleaned the sponges never entered my mind

as it is one of the givens i live by with my tanks

wash in tank water and do water changes

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http://www.skepticalaquarist.com/nitrogen-cycle":p2bx7mig]The pH is also a vital factor in nitrification. Maximum rates of nitrification occur at pH values above 7.2, peaking at 8.3 (a common pH for marine tanks) then falling at higher values. What surprised me was the rate at which the effectiveness of nitrification dropped in acidic pH values: to less than 50% optimal efficiency at pH 7.0, to just under 30% at pH 6.5, and to just over 10% of maximal efficiency at pH 6.0. At these low pH values, nitrifying bacteria don't die, they just stop metabolizing and reproducing. Of course in these acidic conditions, most of the toxic NH3 is ionized to non-toxic NH4.
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try testing it again later this evening and again tomorrow morning and see if it changes - I am still thinking that the tank was doing a mini or minor cycle but ime if ammonia is going to spike it tends to do so more in the evenings.

Hopefully the tank is stabilising.

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Yeah i think you tank is "re cycling". looks like you might have upset the balance a bit by washing your filters a bit too vigorously maybe. Looks like you ammonia has already spiked. There will then be a nitrite spike before it settles down again. Any chance you can raise the PH a little to speed the process up maybe?

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