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Strange cycling problems in established tank


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Hello

 

We have had a tank with one goldfish running for over 4 months now. However something really strange seems to keep reoccuring.

 

We were having ammonia problems, never seeing any nitrite or nitrate even after the tank had gone through its fishless cycle.

 

We kept doing regular water changes and slowly rectified the problem, which initially was caused due to the filter being dirty...

 

Recently we added a plant to the tank also, some of this plant was probably decaying slightly which added a small bio-load to our tank.

 

All of a sudden the ammonia was rising higher, and nitrites/nitrates started to appear! Awesome, Tank is doing a mini cycle and we finally see nitrates, which we had not seen for 3 months (Weird enough)...

 

Unfortunately the plant was in poor shape, one day, we tested the ammonia and saw it was sky high at around 2.0ppm with high nitrites also.

 

So we removed the majority of the plant that was rotting and did a water change to dilute the ammonia and nitrites.

 

The real strange thing is now after this, we tested a day later. Ammonia = 0. Nitrites  = 0. Nitrates = .... 0.

 

I'm aware the nitrifying bacteria live in the filter, so how could removing a plant and changing approx 50% of the water (like for like, PH levels identical etc. to prevent shock)??????????????

 

Still, a few days later this is still the case? What is going on?

 

Another question I have is will it make any difference whether the water trickles past my 3 layers of filtration? Or if it has a chance to "swim" around my biological filter for longer? The bacteria obviously require oxygen but is this through the water or..?

 

I hope some of the people on this forum can provide some insight and advice.

 

(Yes, my filter is large enough, no my tank is not overstocked)

 

Thanks

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If you remove the ammonia and nitrite, no nitrate can be produced.

Also the nitrate test is tricky for some. Read and follow the directions carefully

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Surely doing a 50% water change would not remove all the ammonia and nitrite though?

(If you think it may, what should I do next time to control the ammonia levels when they are high then...?)

 

I'm aware the nitrate test requires vigorous shaking of the bottles before use and before adding bottle 2, we have followed the directions correctly so this is not the issue.

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Could I ask how you cycled the tank? I know you said fishlessly, but outlining the procedure you used would be very helpful in determining the problem. 

 

What filter are you using and how did you clean the filter?

 

What are your tap water parameters? 

 

What size is the aquarium and what size is the filter? ( I'm curious. )

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We need more information to figure out what is going on here.  (I do have a hypothesis and more information might confirm it.)  What would be most helpful is if you filled out the checklist we use for sick fish.  I know some of the questions may seem (and may be) irrelevant, but this is pretty unusual, so we need all the clues we can get.  

 

Please copy & paste fill the following form and fill it out to the best of your ability when requesting help for Goldfish Problems:
Test Results for the Following:
* Ammonia Level(Tank)
* Nitrite Level(Tank)
* Nitrate level(Tank)
* Ammonia Level(Tap)
* Nitrite Level(Tap)
* Nitrate level(Tap)
* Ph Level, Tank (If possible, KH, GH and chloramines)
* Ph Level, Tap (If possible, KH, GH and chloramines)
Other Required Info:
* Brand of test-kit used and whether strips or drops?
* Water temperature?
* Tank size (how many gals.) and how long has it been running?
* What is the name and "size of the filter"(s)?
* How often do you change the water and how much?
* How many days ago was the last water change and how much did you change?
* How many fish in the tank and their size?
* What kind of water additives or conditioners?
* What do you feed your fish and how often?
* Any new fish added to the tank?
* Any medications added to the tank?
* List entire medication/treatment history for fish and tank. Please include salt, Prazi, PP, etc and the approximate time and duration of treatment.
* Any unusual findings on the fish such as "grains of salt," bloody streaks, frayed fins or fungus?
* Any unusual behavior like staying at the bottom, not eating, etc.?

 

One additional question to those on the form and what Chelsea asked:   Do you have a substrate?  If so, what kind and how deep is it? 

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Could I ask how you cycled the tank? I know you said fishlessly, but outlining the procedure you used would be very helpful in determining the problem. 

 

What filter are you using and how did you clean the filter?

 

What are your tap water parameters? 

 

What size is the aquarium and what size is the filter? ( I'm curious. )

:thumbup2:

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Could I ask how you cycled the tank? I know you said fishlessly, but outlining the procedure you used would be very helpful in determining the problem. 

 

What filter are you using and how did you clean the filter?

 

What are your tap water parameters? 

 

What size is the aquarium and what size is the filter? ( I'm curious. )

 

Thanks for the replies :)

 

Initially we were introduced to the whole goldfish thing, with the trap of a fishbowl. After this obviously failed we have done a lot of research and been slowly improving our setup and knowledge.

 

We setup the tank with gravel, conditioned water and filter. We then "fed" the tank with flake food daily, for approx 3 weeks until no more ammonia was seen. So when this occurred, despite seeing no nitrites and nitrates (at the end of the 3 weeks) we assumed that the tank had now cycled, gave it a good vacuum and added Hype.

 

We have a JEBO AP-900 submerged filter, which pumps the water up into a "rangehood" type filter setup. Initially we only had the ceramic bio balls and grey sponge mesh, however we noticed this would get dirty rather quickly and an annoyance to clean, so we added a top layer of the finer cotton about a month ago.

When we clean it now, we siphon out approx 30% of the water and hand rinse the top layer of cotton in the old tank water.

However, sometimes due to high ammonia/nitrites we had seen, we did have to change 50% at times.

Due to wanting to control the higher levels of ammonia and nitrites we were testing daily, and sometimes changing the water every second day when required. 

 

Our tap water has no ammonia, nitrites or nitrates. With a PH of 7.0.

 

Our tank is 33 litres (10 gallons approx.) currently. Our filter is capable of pumping up to 200 litres (approx 50 gallons) an hour.

I am aware this tank is too small in the long term to maintain our goldfish, however it should be sufficient for the short term as Hype is still only... about two inches long from head to tail. We have plans once we move house in the next few months to upgrade to a 50 gallon tank and transfer him then.

 

I will reply to shakaho's post shortly.

 

Thanks again

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Thanks, Hugh. :) 

 

I already noticed a couple of things I would like to point out, if I may:

 

  • You are going to want a pump that pumps 10x your tank's volume per hour. Right now you only have 5x. This isn't enough. However, could you still provide some pics of the current filter? When I went to look it up, all I found was a water pump and not a filter.
  • The tank that you have is only about 8 US gallons, not 10. Here at Koko's we recommend 56-75 liters per fish minimum, with 75 liters being optimal. This is regardless of how small the fish are, so that you have a stable environment (our presenting problem) and don't have to be consistently upgrading. Since young goldfish do most of their growing in the first two years, it's important to have an environment that will be conducive to them growing large, too. 

Also, how thick is the gravel? 

 

Thanks for being so patient with all the questions. It may seem like a lot, but it really helps us to help you. :)

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10x my tank's volume?! I had read elsewhere that 2x my tanks volume or higher should have been sufficient? Is this incorrect?

Currently I am working on site until tomorrow, I will ask my partner if she is able to get some pictures of both the pump and the filter setup and send them through otherwise I'll take some snaps tomorrow.

Your right though, the AP-900 is a water pump which feeds the water up into an inbuilt overhead filter setup.

 

Unfortunately upgrading the tank right now is not easily manageable as the room its in would not easily fit a 4 foot tank or larger. 

 

Initially, the gravel was approximately 1.5 inches thick. When we were trying to troubleshoot our problem we thought perhaps the gravel was our problem, so we removed it all and are currently running with basically a bare bottom tank (there are a few pebbles scattered along the bottom of it). However, as we are still having this issue I was planning on adding back the gravel that we removed? Would you recommend any particular thickness?

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Surely doing a 50% water change would not remove all the ammonia and nitrite though?

(If you think it may, what should I do next time to control the ammonia levels when they are high then...?)

 

I'm aware the nitrate test requires vigorous shaking of the bottles before use and before adding bottle 2, we have followed the directions correctly so this is not the issue.

Sorry i missed the 50% part.

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Removing the rocks could have also removed the bacteria that were processing ammonia, nitrite, and nitrate. Did you notice the timing of removing rocks to correspond with parameter changes?

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10x my tank's volume?! I had read elsewhere that 2x my tanks volume or higher should have been sufficient? Is this incorrect?

Currently I am working on site until tomorrow, I will ask my partner if she is able to get some pictures of both the pump and the filter setup and send them through otherwise I'll take some snaps tomorrow.

Your right though, the AP-900 is a water pump which feeds the water up into an inbuilt overhead filter setup.

 

Unfortunately upgrading the tank right now is not easily manageable as the room its in would not easily fit a 4 foot tank or larger. 

 

Initially, the gravel was approximately 1.5 inches thick. When we were trying to troubleshoot our problem we thought perhaps the gravel was our problem, so we removed it all and are currently running with basically a bare bottom tank (there are a few pebbles scattered along the bottom of it). However, as we are still having this issue I was planning on adding back the gravel that we removed? Would you recommend any particular thickness?

A 75 liter tank isn't that big, it's 76.2 x 33.0 x 33.0cm.

 

10x your tank's volume is the standard for goldfish. What you read elsewhere is incorrect, yes. 

 

Don't add back the gravel, as Lisa said. The fish needs all of the water volume available, and any gravel or ornaments would displace water.

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I wasn't suggesting adding it back. I was just suggesting a reason that a tank thought to be cycled could suddenly experience a bump. The bacteria are dead if the rocks dried anyway.

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You are alright mate, I appreciate the questions and answers in the hope we can get to the bottom of this!

 

That's something I thought of also after the fact.... Although, It wasn't until post gravel removal when we added the elodea plant that the parameter changes seemed to increase significantly...

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If you're sure that is how the timeline was, we found out where the cycle bump likely came from then. 

 

Once you can get some pics of the current filter, we can better advise on how to get everything back on track. 

 

Make sure to fill out Sharon's form completely so that we can get everything in a more manageable format. :)

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Hello

 

We have had a tank with one goldfish running for over 4 months now. However something really strange seems to keep reoccuring.

 

We were having ammonia problems, never seeing any nitrite or nitrate even after the tank had gone through its fishless cycle.

 

We kept doing regular water changes and slowly rectified the problem, which initially was caused due to the filter being dirty...

 

Recently we added a plant to the tank also, some of this plant was probably decaying slightly which added a small bio-load to our tank.

 

All of a sudden the ammonia was rising higher, and nitrites/nitrates started to appear! Awesome, Tank is doing a mini cycle and we finally see nitrates, which we had not seen for 3 months (Weird enough)...

 

Unfortunately the plant was in poor shape, one day, we tested the ammonia and saw it was sky high at around 2.0ppm with high nitrites also.

 

This is what we call a "cycle bump."  Something, perhaps the excess dead plant material,  may have overwhelmed your population of nitrifiers.  Or, as DP suggested, you might have substantially lowered population of nitrifiers because you removed all of the gravel.

 

So we removed the majority of the plant that was rotting and did a water change to dilute the ammonia and nitrites.

 

The real strange thing is now after this, we tested a day later. Ammonia = 0. Nitrites  = 0. Nitrates = .... 0.

 

I'm aware the nitrifying bacteria live in the filter, so how could removing a plant and changing approx 50% of the water (like for like, PH levels identical etc. to prevent shock)??????????????

 

Still, a few days later this is still the case? What is going on?

 

Nitrifiers live on any surface they can find in the aquarium system.  With your rather small filter,  a  larger proportion of  the nitrifiers would live in the tank than would be the case if you had a HOB filter that turned over 10X the tank volume per hour.  With the larger filter, the filter medium is by far the best place for the biobugs to live.  They have lot of surface in the biomedium to grow on, and a steady stream of water containing oxygen and ammonia.  

 

When you did a 50% water change, You cut the amount of ammonia, etc. in half.  This was a quantity your smaller population of nitrifiers could handle so ammonia and nitrite go away and stay away.

 

Another question I have is will it make any difference whether the water trickles past my 3 layers of filtration? Or if it has a chance to "swim" around my biological filter for longer? The bacteria obviously require oxygen but is this through the water or..?

 

They get ammonia and oxygen from the water flowing through.  

 

Please read our guidelines for keeping goldfish.  

 

I wonder where you read that an aquarium filter should turn over 2x the tank volume per hour.  The only situation under which I have heard such a recommendation is for ponds, where that goes along with a separate external  filter that has 1/10 the volume of the pond.   With aquarium filters, a larger turnover goes along with a larger volume for filter media.  

 

I am not at all concerned about the size of your tank for now.  However, in a few months, your 2 inch fish will be 4 inches long.  It will also be twice as wide and twice as "tall."  That means it will have 8 times its current volume/mass, and will be producing 8 times the waste it produces now.  A larger volume of water dilutes waste.  The other way you dilute waste is with water changes.  When you read our guidelines, you will see we recommend a minimum of one 50% water change per week.  You can compensate for a small tank by doing larger and/or more frequent water changes.  I would recommend two 50% water changes each week until you get that big tank.

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* Ammonia Level(Tank)

0-0.25 ppm max atm.


* Nitrite Level(Tank)

0ppm


* Nitrate level(Tank)

0 ppm or very close to it. (isn't this strange..? considering the tanks been running for 3 months)


* Ammonia Level(Tap)

0ppm


* Nitrite Level(Tap)

0ppm


* Nitrate level(Tap)

0ppm


* Ph Level, Tank (If possible, KH, GH and chloramines)

7.5

Do not have KH, GH tester available.

When we do a water change we are adding "Aquasonic's Goldfish Water Conditioner" to raise the hardness and salinity


* Ph Level, Tap (If possible, KH, GH and chloramines)

7.0


Other Required Info:
* Brand of test-kit used and whether strips or drops?

API Freshwater Master Test Kit, drops.


* Water temperature?

22 degrees Celsius (71.6 farenheit)


* Tank size (how many gals.) and how long has it been running?

8.7 gallons, has been running for 3 and a half months.


* What is the name and "size of the filter"(s)?

JEBO AP-900 submersible pump, capable of pumping 200 litres an hour (approx. 50 gallons an hour), feeding into a “rangehood” overhead tray, which has the ceramic bio balls on the bottom, grey mesh in the middle and the finer cotton on top.


* How often do you change the water and how much?

Ideally we aim for approx. 30% weekly, however when we see higher ammonia level’s we have sometimes had to do this every second day, anywhere between 30-50%.

When we do complete water changes, we add a small amount of bicarb soda, to bring the tap water PH to the same as our tank water to prevent stressing our fish.


* How many days ago was the last water change and how much did you change?

3 days ago, 50% was changed as our ammonia was reading between 1.0 – 2.0 ppm, nitrites were reading around 1.0 – 2.0 ppm and nitrates were reading around 20ppm.


* How many fish in the tank and their size?

1 celestial eyed goldfish, about 2 inches max head to tail


* What kind of water additives or conditioners?

We use Fraction, which is supposedly made by the same people that make Prime just a newer form.


* What do you feed your fish and how often?

We feed a mixture of pellets that we soak first, and flakes also. Twice a week we feed a de-shelled pea also.

We only feed once a day at the moment and any uneaten food after 2 minutes we scoop out.


* Any new fish added to the tank?

No. Hype is the only inhabitant. We did add the elodea plant recently though as mentioned in my first post


* Any medications added to the tank?

No, trying to avoid needing this.


* List entire medication/treatment history for fish and tank. Please include salt, Prazi, PP, etc and the approximate time and duration of treatment.

None.


* Any unusual findings on the fish such as "grains of salt," bloody streaks, frayed fins or fungus?

Once I saw a small grain of salt like thing on Hype, but it then disappeared and have not noticed anything else recently.


* Any unusual behavior like staying at the bottom, not eating, etc.?

He likes to sleep at the bottom at times and sometimes he also appears to be gasping for air (rarely).. But we do have an airstone pumping in oxygen and the water parameters currently are as stated above, so I do not see why he would be doing this from time to time either?

He still loves to eat.

 

 

One additional question to those on the form and what Chelsea asked:   Do you have a substrate?  If so, what kind and how deep is it? 

We had approx. 1.5 to 2 inches of gravel substrate, but thought this may have been causing the problem of High ammonia so removed it and at the moment it is essentially a bare bottom tank with pebbles littered over it.

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Nitrifiers live on any surface they can find in the aquarium system.  With your rather small filter,  a  larger proportion of  the nitrifiers would live in the tank than would be the case if you had a HOB filter that turned over 10X the tank volume per hour.  With the larger filter, the filter medium is by far the best place for the biobugs to live.  They have lot of surface in the biomedium to grow on, and a steady stream of water containing oxygen and ammonia.  

 

When you did a 50% water change, You cut the amount of ammonia, etc. in half.  This was a quantity your smaller population of nitrifiers could handle so ammonia and nitrite go away and stay away.

Ok Thanks for this information. We will be looking into getting a bigger tank and filter in the near future. 

In the mean time, if with the water change and removal of the plant this population of bacteria could handle the ammonia/nitrite... Is there a reason we see no nitrates at all? Based on my understanding of the cycle this still seems a tad strange no?

 

Another question I have is will it make any difference whether the water trickles past my 3 layers of filtration? Or if it has a chance to "swim" around my biological filter for longer? The bacteria obviously require oxygen but is this through the water or..?

 

They get ammonia and oxygen from the water flowing through.  

So.. sorry for asking the same question again I jsut want to ensure I understand properly, does it make any difference at all if i allow the water to "pool up" in the filter, or just briefly flow past it and back in the tank

 

 

Please read our guidelines for keeping goldfish.  

 

I wonder where you read that an aquarium filter should turn over 2x the tank volume per hour.  The only situation under which I have heard such a recommendation is for ponds, where that goes along with a separate external  filter that has 1/10 the volume of the pond.   With aquarium filters, a larger turnover goes along with a larger volume for filter media.  

 

I am not at all concerned about the size of your tank for now.  However, in a few months, your 2 inch fish will be 4 inches long.  It will also be twice as wide and twice as "tall."  That means it will have 8 times its current volume/mass, and will be producing 8 times the waste it produces now.  A larger volume of water dilutes waste.  The other way you dilute waste is with water changes.  When you read our guidelines, you will see we recommend a minimum of one 50% water change per week.  You can compensate for a small tank by doing larger and/or more frequent water changes.  I would recommend two 50% water changes each week until you get that big tank.

Thanks for your help we shall try this whilst sourcing the next upgrade

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When you did a 50% water change, You cut the amount of ammonia, etc. in half.  This was a quantity your smaller population of nitrifiers could handle so ammonia and nitrite go away and stay away.

 

Ok Thanks for this information. We will be looking into getting a bigger tank and filter in the near future. 

In the mean time, if with the water change and removal of the plant this population of bacteria could handle the ammonia/nitrite... Is there a reason we see no nitrates at all? Based on my understanding of the cycle this still seems a tad strange no?

 

Quite frankly, nitrate concentration can be weird. There are three major ways nitrate can be removed from an aquatic system -- water changes, uptake by terrestrial or marginal plants (aquatic plants prefer ammonia as a nitrogen source, but some algae are very happy with nitrate), and denitrification.   Denitrification takes place under anaerobic or anoxic conditions.   These can occur just under the surface of the substrate, in the muck at the bottom of a pond/lake, or in a poorly aerated filter.  I am not familiar with your filter, but  looking at the pictures, this looks like a filter that has anaerobic pockets.  I think this is where your nitrate is going.  Removing nitrate is good, but having anaerobic conditions in your filter decreases nitrification, which is bad. 

 

 

 which shows how to make a moving bed filter for your aquarium.  It appears to be very cheap and easy to make.  If I kept aquariums, I would definitely make one.  (I have ponds.)  Of all filters in which the medium is submerged in water, moving bed filters are most efficient at nitrification.  If you made one of these and ran it along with your current filter, you would go from having unstable filtration to having super filtration.  

 

 

Another question I have is will it make any difference whether the water trickles past my 3 layers of filtration? Or if it has a chance to "swim" around my biological filter for longer? The bacteria obviously require oxygen but is this through the water or..?

 

They get ammonia and oxygen from the water flowing through.  

So.. sorry for asking the same question again I jsut want to ensure I understand properly, does it make any difference at all if i allow the water to "pool up" in the filter, or just briefly flow past it and back in the tank

 

Yes.  Water that pools in the filter quickly becomes anaerobic as the nitrifiers (and other critters) gobble up the oxygen.  Nitrification stops in the absence of oxygen. (Contrary to popular fishkeepers legends, the nitrifiers survive anoxia in an inactive state).

 

Aquarium filters have so little substrate for the nitrifiers to grow on that one passage through the filter cannot remove all ammonia.  You have to get the same water through the filter many times.  I suspect the cotton you are putting in the filter has decreased the flow rate far below its optimum and is one of your problems.  

 

 

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  • 2 weeks later...
  • Regular Member

Firstly, Thanks to all for the time taken in providing your responses!

 

I have one last question.

 

The recommendation for filtration is 10x the tank's volume. For example a 50 gallon tank, should be filtered by a total of 500 GPH filtration or greater.

 

Manufacturer spec's are very rarely what they actually turn over in the "real world". Some canister filters may be rated at say... 525 GPH, but when connected underneath a tank may only actually turn over 50-75% of that rated specification. E.g. 315 GPH.

 

My question is : Is this still sufficient filtration? (Is the recommended 10X turnover value, based on manufacturer specs or ACTUAL turnover?)

 

Thanks in advance :)

Edited by hughesyau
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