Newb Mistake - Mini Cycle

Nitrite binds to the haemoglobin in the fish's blood and blocks the oxygen receptors. It does the same to fish as carbon monoxide does to us. There is no non-toxic form of nitrite as there is with ammonia. You need to remove the nitrite by water changes, I'm afraid.

You could try using Prime as your dechlorinator. This claims to detoxify nitrite though as they won't say what's in it, no-one can be sure. But you will still need to do water changes as the effect only lasts about 24 hours.

Get some Tetra Safe Start as this does contain the correct species of nitrite eaters. Pour it into the filter rather than just into the water.



There is another thing you could try but it's a bit fiddly. Salt, ordinary salt, can be used as the chloride part blocks nitrite from entering through the gills. It is best to use pure sodium chloride - that can be found in fish shops as 'aquarium salt'. The salt we use in cooking has anti-caking agents added, and in some countries iodate is also added.
Now for the fiddly bit.

• measure the nitrite level
• multiply it by 10 (this gives the amount of chloride needed for the nitrite level in mg/l)
• calculate the volume of water in the tank in litres
• multiply the numbers from 2 and 3 (this tells you how much chloride the tank needs)
• multiply 4 by 1.5 (salt is only 2/3 chloride)

The number from 5 is the amount of salt you need in mg. Divide by 1000 to get it in grammes.

Weigh the salt and dissolve in a bit of tank water in a tub. When it has all dissolved, pour it into the tank.

If the nitrite level goes up again, subtract yesterday's reading from today's to see how much extra nitrite is in the water, then use that extra nitrite figure in the calculation and add more salt.
When nitrite drops to zero, daily water changes will gradually remove the salt.

I forgot to mention - if nitrite gets to around 15 to 16 ppm the nitrite eaters will stop multiplying. However, our test kits don't measure that high. Water changes and using Safe Start are the better options - water changes to make sure nitrite doesn't get that high, and Safe Start to add bacteria.

Sorry to hear that you've lost some of your fish.
Keep up the water changes and let us know how you get on.
Best of luck.

Thanks all

Ok new levels after work today. 18 hours after completing 50% water change and adding Safe Start. Maybe very slightly better than immediately after but no worse. So hopefully we are moving along and will be good now.

Hi @Aquaaggie

In order to ensure that the Tetra SafeStart works quickly, do you have figures for the tank water temperature, pH and KH? It would also be handy to know your GH. Are you using the NT Labs Multi-Test Kit or the API equivalent? Do you have any plants in your tank?

JPC

Temp 79-80
Ph 7.8
GH 9
KH 6

Using the API kit

Have about 18 leaves of an Anubis species and ~4 feet of hornwort.

Nitrites have been holding somewhere between 0.5-1 for last two days (still need to test today) without water changes. Very slight improvement each day, but definitely not getting worse.

Plants were not added till after the initial cycle but before this all started. They look fine. Hornwort looks good at the tops, I anchor it down to have it grow vertically and the deeper parts always look a little shaggy. It’s been growing 0.5-1 inch per day. It really doesn’t seem like that much plants for a 69 gallon

Hi @Aquaaggie

In the short term, my hunch is that the plants will be the main processor of ammonia, nitrite and nitrate. And the nitrification in your filter will take time to get established. But, how long it will take is uncertain.

In my last post, I asked about lighting and fertlization - any information would be helpful. I don't think we should be adding plant fertilizers that contain nitrogen. I am also wondering if enough oxygen is getting into the water. During the day, your plants will help to oxygenate the water. But, overnight, oxygen level will probably drop. Adjusting the position of your filter outlet to increase surface agitation will help to oxygenate the water. Nitrifying bacteria also need a good supply of oxygen as nitrification is a process of oxidation.

Please let us have an update about your tank and inhabitants. What's the latest?

JPC

Also have logged into my computer to see if I can load a picture of the tank.  I have a bubble wall and 7 other bubblestones, so I don't think oxygenation is a problem

Hi @Aquaaggie

Thanks for the photo, which is very helpful. There is far less Hornwort in your tank than I had imagined. I think you said previously that there was approximately 4 feet of it. Is your substrate just inert gravel/sand or do you have a bottom layer of soil, for example? As you are not planting into the substrate, there would be no need for soil.

Contrary to what I said previously, it looks like the Tetra SafeStart is already doing its job.

Please keep us updated.

JPC

Yey  congratulations I would want to wait 2 weeks minimum before adding any more fish. Only add a third of your current stocking in cms at a time is a rule I’ve followed successfully in the past