My tank crashed

The friendliest place on the web for anyone with an interest in aquariums or fish keeping!
If you have answers, please help by responding to the unanswered posts.

Rishil

Aquarium Advice Newbie
Joined
Jan 14, 2022
Messages
8
I have freshwater tropical tank 125 litre with canister filter.
Last week my tank filter blocked and I washed with tank water and I reffiled the tank. Before I wash it was measuring pH 7.0 and everything was zero and the tank was cycled.
After I wash, I started getting reading of ammonia I was dosing prime to protect the fishes are inside.
From yesterday I ammonia start to building up and I start see a bacteria bloom. My last check was showing pH 7.0 ammonia 4.0 nitrite 0.25 And last nitrate 5.0.
Not sure what to do.
Please help
Thanks
 
First off. No immediate panic. At your pH and a typical aquarium temperature 4ppm ammonia isnt an immediate threat to fishes health. That can quickly change though and needs to be rectified.

How long did it take to go from zero ammonia to 4ppm ammonia? If that happened in a short space of time (a day or 2) you are either overstocked or something else is contributing to your ammonia. Just check your water source for ammonia.

You need to recycle the tank as you would for a fish in cycle. Water changes sufficient to keep ammonia + nitrite combined below 0.5ppm. So from where you are now you need to 3 x 50% water changes. Maybe do them an hour or 2 apart.

Using prime as your water conditioner will detoxify some ammonia for a short space of time, but the only surefire way to remove ammonia with no cycle is water changes.

A good way to speed up the cycling process would be to put a small amount of filter media from an established filter into your filter, or get a sponge from an established filter and squeeze it into your tank water. Perhaps you have a friend who keeps fish who could let you have some? This will seed your filter with the bacteria you are trying to grow and speed up the process.

Another option is bottled bacteria like Dr Tims One + Only or Tetra Safestart. These products wont instantly cycle a tank as they claim but in a similar manner to adding established filter media they can seed your filter with the bacteria you are trying to grow to establish your cycle. These products are hit and miss as to whether they work at all, but are an option if established filter media isnt obtainable and may speed up the process from several months to several weeks.
 
Hi Aiken
Thanks for answering so quickly. Ammonia started building up from last 2 to 3 days. I don't have anyware where to put the fishes. I dont have other choice, cycle with fish this time. I know it's harsh decision but I don't have choice.
Do you think the cycle crashed?
If I do water change all nitrite will go also the cycle will be backwards.
Thanks
 
If you are seeing ammonia and nitrite then either your cycle crashed or there is another source of ammonia that your cycle cant cope with. Its possible something died, its possible your water company did some work and flushed the system with chloramine. Given it happened after you cleaned the filter that's the most likely cause though.

How long was your filter blocked? If water flow dropped to much for too long that could have killed off your cycle?

If you can keep up with your water changes cycling with the fish should be relatively safe. That might be a lot of water changes depending on how heavily stocked you are, but you dont really have any other option. Prime will only detoxify ammonia so far. If your cycle is gone the ammonia will eventually build to a point where prime won't be effective any more.

Yes, doing such large water changes will take all the nitrite out of the tank and slow down the nitrite to nitrate stage of recycling. But how can you remove the ammonia without also removing the nitrite? As your cycle develops and your ammonia to nitrite stage develops, you wont have any shortage of nitrite to push that along.

Just keep ammonia + nitrite combined at a safe level of 0.5ppm. This will leave enough waste to cycle your tank while keeping relatively safe.
 
The filter was running before I clean but the flow was very poor.
I will do 50% water change now. I m using quick start form API and normally I use tap safe from tetra but I will use prime.
If I keep doing water changes when my tank will be cycled?
 
Cycling a tank typically takes 6 to 8 weeks. If you didnt completely crash/kill off your cycle it might take less time. It often takes longer. No way to say how long yours will take, it takes as long as it takes.
 
Last edited:
Is worse case scenario kill the cycle. No one specifying what is the point to kill the cycle. Everybody says different. I know cycle the tank takes time.
 
Im sorry. I dont understand what your point is.

You arent trying to crash/kill your cycle. Thats what has happened.

You are trying to re-establish your cycle. This takes time, and while it re-establishes you need to keep your water parameters safe and your fish alive by regular water changes.

Regularly test the water for ammonia and nitrite. At least daily.

Your target should be to keep ammonia + nitrite combined no higher than 0.5ppm by changing water whenever your water parameters exceed this target. 0.5ppm combined is a level of waste that is sufficient for your cycle to establish but relatively safe for your fish.

If you see 0.5ppm ammonia and 0.0ppm nitrite (0.5ppm combined) then leave things be. If you see 0.5ppm ammonia and 0.25ppm nitrite (0.75ppm combined) then change 1/3 of the water. If you see 0.25ppm ammonia and 0.75ppm nitrite (1.0ppm combined) then change 1/2 the water. If water parameters get worse than these levels it may require multiple daily 50% water changes to maintain safe water conditions. This is more likely to happen with a fully stocked tank.
 
Last edited:
Other forums. I was checking.

I did a water change yesterday and today 3.
I did a test and the results are pH 7.0, ammonia 1.0, nitrite 0.0 and nitrate 0.0 and then I did my last water change.
All water change is 50%.
My fishes looks healthy and no casualty.
I hope everything is going in a right direction
 
Looks like you’re getting the water parameters back to a more safe level

I would have to agree, for some reason when you cleaned the filter, you’ve lost enough beneficial bacteria that the cycle was lost. If you cleaned the filter with tank water, I would have to assume there’s still some amount of beneficial bacteria left, so it shouldn’t take the full 6-8weeks to re-establish the cycle.

Keep up with the water changes for now, and try not to let the ammonia get up to or above 1ppm. You also don’t want to do excessive water changes and get the ammonia to a 0 reading or you will make the cycle take longer to establish
 
Hi @coldkoi. I assume the same I lost the cycle.
I did water change again this morning and I checked just now.
pH 7.2
Ammonia 0.50
Nitrite 0.0
Nitrate 0.0

I keep the water with no water change

I will check again tomorrow and will see how is looks like it.

Thanks for your help and support.
 
Hello guys. Thank you for your help and support, the results on my tank from past 3 days is back to normal
pH7.2
Ammonia 0.0
Nitrite 0.0
Nitrate 0.0

I think the nitrogen cycle is complete our recovered. Don't know ....

I hope the results keeps like this.
 
Hello.

No water changes. Last water change was on 16 Jan .
Untill today no issues.
 
I would question your test readings then. Make sure you are doing the tests correctly, especially nitrate test. Really shake the heck out of bottle #2 on the nitrate test. Like bang the bottle on the countertop.

If you are cycled you should see some nitrate. If you arent cycled you should see ammonia and/or nitrite depending on how progressed your cycle is. Seeing nothing doesnt make sense unless you are testing immediately after a very big water change.

Edit. Im assuming there are fish in the tank?
 
This is all very confusing, not so much to me but to the original poster Rishil. Seems you're getting too many opinions, and probably many inexperienced opinions. We don't exactly know why your tank "crashed". Re-cyclying your tank all over again should not be a big deal "if" you follow what Aiken has clearly detailed for you... providing you left some bacteria behind after cleaning your filter. I can guarantee your testing results of the water is not accurate or consistent with the "norm". You say your fish look fine, that's a good indication you are doing something good but if your system crashed as you say, frequent water changes will be the way to go since you are basically doing a "fish in cycle". In time, if the filter is properly running and you don't overfeed, you'll be back in shape.
 
Back
Top Bottom