Help with ammonia spikes!!?

[Annep23]

I have a 90 gallons freshwater tank with 12 small fish in it. I have had it for about 2 years with no problems. In the past 2 months the ammonia levels have spiked to lethal levels after water changes and have killed many fish. It just happened two random times and I cannot figure out why and how to stop it from happening again. I do a water change every 2 weeks, about 20%, and siphon the gravel with each change. I usually don't touch the filter for about every other month. Any help would be appreciated because I am lost!??? Right now I have the remaining fish in a hospital tank but can't keep them there for long as there is too many in there for the size of the tank. Please help! Thanks


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[dalto]

What are your ammonia readings when they spike?

 

[Annep23]

They are usually anywhere from 1-2.0 ppm. I didn't notice either time it happened until I saw all the fish at the top of the tank gasping for air. The first time it was at least 2ppm. This spike is between 1 and 2.


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[Annep23]

This is my first aquarium so maybe I've been lucky the past months with no problems cuz this is all a learning process for me


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[dalto]

Have you tried testing your tap water?

Also, are you treating the water with anything during your water changes?

 

[Annep23]

I did test the tap water and it was zero ammonia and fine with everything else too. I treat the water with prime or API stress coat depending on which I have. Could it be a filter issue? I have an under gravel filter, a fluval but not sure which model right now.


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[Sillyfishies]

I did test the tap water and it was zero ammonia and fine with everything else too. I treat the water with prime or API stress coat depending on which I have. Could it be a filter issue? I have an under gravel filter, a fluval but not sure which model right now.


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My bet is on the undergravel filter. All that gunk it's collecting in the past 2 years is finally starting to pollute your water faster then you can clean it. I suggest doing a REALLY! good gravel vaccum, then take out the UG and change to normal substrate. Sand is best. Play sand or pool filter sand works great. Also, try to leave the fluval alone as much as possible because you're taking out a lot of bacteria.

 

[Annep23]

My bet is on the undergravel filter. All that gunk it's collecting in the past 2 years is finally starting to pollute your water faster then you can clean it. I suggest doing a REALLY! good gravel vaccum, then take out the UG and change to normal substrate. Sand is best. Play sand or pool filter sand works great. Also, try to leave the fluval alone as much as possible because you're taking out a lot of bacteria.

Wouldn't I be removing beneficial bacteria that's in the gravel too by super cleaning it and removing it? Can I use a mix of sand and gravel?

 

[dalto]

Wouldn't I be removing beneficial bacteria that's in the gravel too by super cleaning it and removing it?

Yes, in a UGF the bacteria is in the gravel. I am nit really sure how hard it is to dislodge the bacteria through cleaning. Need a UGF expert to chime in.

... then take out the UG and change to normal substrate. Sand is best. Play sand or pool filter sand works great. Also, try to leave the fluval alone as much as possible because you're taking out a lot of bacteria.

I thought the Fluval was the undergravel filter. Maybe I wasn't understanding.

 

[Sillyfishies]

Yes, in a UGF the bacteria is in the gravel. I am nit really sure how hard it is to dislodge the bacteria through cleaning. Need a UGF expert to chime in.


I thought the Fluval was the undergravel filter. Maybe I wasn't understanding.

I just reread and I think you are right. I thought he was saying he had an ugf and a fluval filter. And if your getting ammonia spikes, you don't have enough bacteria anyway, so your going to have to go through a mini-cycle. Just keep some of the gravel to seed the new stuff and get a good canister/HOB filters.

 

[Annep23]

What happened to all the bacteria that I had for the past 2 years? And why did it just start to happen now? In my fluval filter there are 4 compartments on one side. What should I have and in what order should be in those?

 

[dalto]

What kind of Fluval filter is it?

 

[Annep23]

Fluval 406 canister filter. Thank you so much for your help

 

[dalto]

OK, so now I understand. You have an undergravel filter and a Fluval 406 canister attached to a 90 tank. There are 12 fish in the tank.

There doesn't really seem to be anything wrong with that scenario. But when you do a water change your ammonia spikes to 1-2ppm.

What media do you have in the filter baskets now?

One last question before a better recommendation.

What are those 12 fish?

 

[Annep23]

I'm sorry I didn't explain my set up well, I'm new to this still, so thanks for your patience. I have 1 red tip catfish/shark (it's about 4.5 inches), 2 hatchet fish, 4 rainbow fish, 2 cichlids (don't remember what kind but they stay on bottom and don't bother other fish), 3 rasbora .

In the filter there is carbon, phosphate removing pads, the little bio media cubes, and the sponge filters with purigen packets in there with them. A co worker helped me set it up so that is what he put in.

 

[dalto]

That is an awful lot of chemical filtration you have in that canister.

carbon, phosphate removal pads and purigen.

Typical canister media works something like this, mechanical(coarse foam, ehfimech, etc)->bio->chemical(optional)->fine polishing media. Some people put the polishing media before the chemical media.

I think on the 406 the course foam runs up the other side. Then you have 3 types of chemical media. Then you have some bio and a type of sponge. Maybe bio-foam which is a moderately fine foam.

Some general notes on your chemical filtration. Carbon is consumable needs to replaced over time. IMO, there is little reason to run both carbon and purigen. THey do the same thing and Purigen is quite a bit better at it. Purigen needs to be recharged once it turns brown so keep an eye on that. Lastly, do you have a Phostphate problem in your tap water? phosphate removing pads are not a typical throw in unless you have a specific issue to correct.

All that being said, I don't think that is your issue. Moreover, screwing around with your canister filter is not likely to help matters right now.

Back to the problem at hand, I am a little perplexed. Your fish load doesn't sound like it is very high unless those 2 mystery cichlids are bigger than I am thinking. You have two filters on your tank. Your tap water has been tested.

The only thing I can think of is that you are disturbing too much of your BB when cleaning your gravel. But honestly, I don't know enough about UGFs and maintenance to feel strongly about that. Hopefully someone more familiar with UGF's will jump in.

 

[Annep23]

In the future I can take out my carbon and just use purigen. I have recharged it before so I try to stay on top of that. We had a phosphate issue in well water so that's why the pads were in there. I was thinking maybe I somehow disturbed too much of the bacteria in the gravel too but when you siphon do you just do the top portion of the gravel or do you push the siphon down into the gravel and stir it up. Maybe I'm doing it wrong? As for the mystery cichlids they are small, like maybe 3 inches at most, and I took them as a re-homing issue because someone was getting rid of their tank (I know it's random to put them with my other fish) I appreciate all the help and advice you have given me!! Thank you. I hope someone that knows a lot about the ugf will try to help me also.

 

[Sillyfishies]

In the future I can take out my carbon and just use purigen. I have recharged it before so I try to stay on top of that. We had a phosphate issue in well water so that's why the pads were in there. I was thinking maybe I somehow disturbed too much of the bacteria in the gravel too but when you siphon do you just do the top portion of the gravel or do you push the siphon down into the gravel and stir it up. Maybe I'm doing it wrong? As for the mystery cichlids they are small, like maybe 3 inches at most, and I took them as a re-homing issue because someone was getting rid of their tank (I know it's random to put them with my other fish) I appreciate all the help and advice you have given me!! Thank you. I hope someone that knows a lot about the ugf will try to help me also.

I'm willing to bet the cichlids are german blue rams, bolivian ram, or an apistogramma of some sort.