Do Not Know Whether My Cycle Has Stalled.

If your ammonia is that low, you need to add more. or do you mean it drops to 0.25 a day after adding a dose of ammonia?
The second stage, growing the nitrite eaters, is the longer of the two. These bacteria seem to take about twice as long to grow as the ammonia eaters do. To be honest, 18 days isn't that long. I've come across people who are still cycling after 3 months!

One other thing to check - what is the pH of the tank water? If your carbonate hardness (KH) is low there won't be enough carbonate to stop the pH dropping with all that acidic nitrite the bacteria are making. Both bacteria grow best at pH's in the high 7's so if your has dropped below 6.5, they will stop multiplying. If your pH has dropped that low, report back and I'll tell you what to do 

In that case, you could try doing a big water change to get the nitrite reading down a bit. A lot of people find that helps. High nitrite can inhibit the growth of the nitrite eating bacteria, so lowering the nitrite level allows them to multiply faster.

Look on it as practising for when you have fish  You'd be surprised the number of newcomers posting on fish forums because they can't manage to use a siphon tube.

Tommorrow's fine, it's not like you have fish that could be poisoned if you leave it 

Try 50% and see what the nitrite level is after - wait 20 mins or so for the new and old water to mix thoroughly before testing. If it reads somewhere between zero and the highest colour on the chart, that's fine. Wait till your usual time before adding more ammonia.

Can I ask, what is the nitrate filter? I've not come across anything that attaches to a tap that removes nitrate 

What brand test kit are you using for nitrite; what's the highest it can measure?

I've got the API one too, I needed to check as different makes have a different maximum.
Since 5ppm is the highest it can measure, all you can say is that before the water change, the level was somewhere above 5ppm. Anything from 5 upwards will show as 5.
You say you changed 5 x 12 litres, ie 60 litres so you changed just over a third of you 160 litres. As you now have somewhere between 2 and 5ppm, before the water change, your nitrite would have been between 6 and 15ppm. The water change has brought the reading down to a colour on the scale rather than off the top, which is what you wanted it to do. Hopefully, you'll find the cycle speeds up a bit now - though don't forget you are in the slower of the two stages.


I've googled that nitrate remover, I'd not come across it before. Since it's an anion exchnge resin it should be fine, it's cation exchangers you have to be careful with. They remove calcium mainly (used as water softeners) and alter the water chemistry to something you don't want in a fish tank.


Do you intend using the nitrate remover when you have fish? With a few exceptions, most fish can cope easily with 40ppm nitrate, but if you want one of those nitrate sensitive species it will help.

You say you changed 5 x 12 litres, ie 60 litres so you changed just over a third of you 160 litres. As you now have somewhere between 2 and 5ppm, before the water change, your nitrite would have been between 6 and 15ppm.

I don't dare disagree too often with Sue's posts, but her arithmetic in this case is flawed!  If your readings are now somewhere between 2 and 5ppm, before the water change, your nitrite would have been between 3 and 7.5ppm.

I'm not sure this makes much difference to the post but errors like this make my bones itch.  The only relief I get is to correct them! 

Quote from: Sue on November 12, 2012, 02:53:35 PM

You say you changed 5 x 12 litres, ie 60 litres so you changed just over a third of you 160 litres. As you now have somewhere between 2 and 5ppm, before the water change, your nitrite would have been between 6 and 15ppm.

I don't dare disagree too often with Sue's posts, but her arithmetic in this case is flawed!  If your readings are now somewhere between 2 and 5ppm, before the water change, your nitrite would have been between 3 and 7.5ppm.

I'm not sure this makes much difference to the post but errors like this make my bones itch.  The only relief I get is to correct them! 

Quite right Steve, I did make a mistake  My figures would have been right for a two thirds water change, not a one third.

My appologies Mervyn.


It just goes to show you shouldn't believe everything you read on the internet.



That's the problem with those light bulbs and the ammonia test.
The interesting thing is that when the comapct fluorescent bulb in our bedroom went, none of the shops I tried for a replacement sold them. So I got a halogen bulb instead, they were everywhere. Much better even if they use more electricity! I have since found compact fluorescents on sale, but I'm not going back to them unless they ban halogens too.



Edited because my typing is even worse than that calculation!

I'm keeping my fingers crossed for the LEDs. I would hate to have to go back to compact fluorescent. The bedroom one that went was white, something I hadn't seen for ages. We had a spare lower watt one, but that turned our pink walls orange and the dark red curtains a really horrible colour. Heaven knows what an ammonia test would have read under it. Or a nitrite come to that!


Hmmm, I can see me stockpiling halogen bulbs if LEDs haven't taken off by then.

That probably explains it - the temporary bulb was from a pack of free ones from the electric company. I was afraid I'd just be throwing money away buying one of the right watts, even  though I couldn't find any in the frist shops I tried.



Sorry Mervyn, I'll try and get back to your subject from now on!