15 Gallon Tank Did my cycle just crash? What do I do?

Hi guys,

Need some help on my freshwater tank.
I have a cycled 18 gallon tank with a cannister filter.
It has been set up for almost 6 months.
It is stocked with 3 dwarf puffer, 8 neon tetra and 2 otos.
It is a planted tank, no CO2.

Recently I have noticed that my nitrate is constantly high. Its between 20 to 40 ppm even though I do water changes.

My tap ph is usually 6.4 to 6.6 so I have been using crushed corals and it was a steady 7.2 for months. Now it has been gradually dropping.

Today's water test shows ph 6.6, ammonia 0.5, nitrite 0, nitrate 40.

I have dosed my tank with Prime.

I dont know what is going on.
Would really appreciate any help I can get.

 

Well, puffers are messy so that is likely the cause of your nitrates, without co2 the plants can’t make use of enough of them.

you can leave the light on for longer, add some floating plants, switch to a more powerful light, add co2

or increase water changes.

a likely culprit past puffers just being messy can be fertilizers are you dosing any fertilizers currently?

 

I just upgraded my lights yesterday. 39W.
My lights are on 8 hours a day.
I dose excel and comprehensive once a week.
My plan is to upgrade to a co2 system.. but only in a month or two.

 

I yeah I’d cut out or reduce the dosing and let the plants grow

 

Okay. I will do that. Thanks for the advice.

Is the sudden ammonia linked to this as well?

 

Can be, short of you doing something like removing all the biological media or dosing with some strong medication the cycle shouldn’t just crash

I briefly played with fertilizers in my planted tanks and it was all headaches.
Once you do run co2 they can be helpful but it’s really going to depend on your plants, for allot of the staple aquarium plants a dirted tank and/or root tabs is far more effective and stable than liquid fertilizers will be.

 

My tank has gravel but i do use root tabs for the plants.
In general everything seems to be falling apart.. the plants don't seem healthy, the water readings are bad.
I am at wits end.

 

Hi guys,

Need some help on my freshwater tank.
I have a cycled 18 gallon tank with a cannister filter.
It has been set up for almost 6 months.
It is stocked with 3 dwarf puffer, 8 neon tetra and 2 otos.
It is a planted tank, no CO2.

Recently I have noticed that my nitrate is constantly high. Its between 20 to 40 ppm even though I do water changes.

My tap ph is usually 6.4 to 6.6 so I have been using crushed corals and it was a steady 7.2 for months. Now it has been gradually dropping.

Today's water test shows ph 6.6, ammonia 0.5, nitrite 0, nitrate 40.

I have dosed my tank with Prime.

I dont know what is going on.
Would really appreciate any help I can get.

Well, as long as Nitrate is being produced (even it keeps climbing), and your Nitrite and Ammonia is low, you really just looking at water changes required.... Maybe your choice of food produce a lot of waste?

 

Well, as long as Nitrate is being produced (even it keeps climbing), and your Nitrite and Ammonia is low, you really just looking at water changes required.... Maybe your choice of food produce a lot of waste?

I have been doing daily water changes. Around 15% to 20%.
Since i have dwarf puffers, i feed them bloodworm. The neons are absolute gluttons, i have stop feeding them pellets because they eat the bloodworms as well.

 

I have been doing daily water changes. Around 15% to 20%.
Since i have dwarf puffers, i feed them bloodworm. The neons are absolute gluttons, i have stop feeding them pellets because they eat the bloodworms as well.

Ok. if you have been doing daily change... try not to vacuum the gravel everyday, you can in theory disturb the bacteria colonies too much, which 'can' affect your biofilration. Just water change (conditioned of course) is of course ok.

 

Ok. if you have been doing daily change... try not to vacuum the gravel everyday, you can in theory disturb the bacteria colonies too much, which 'can' affect your biofilration. Just water change (conditioned of course) is of course ok.

Oh no! I have been doing gravel vac daily... I will stop that. Thanks for the advice.

 

You may need to add more CC. Have you pulled it out and cleaned it? If not you may want to do so. I use CC to stabilize my pH. I check the pH from time to time. When it starts dropping I know it is time to either clean or add more. I use the chunks of coral. It is in a media bag in my HOB filter. Once a month or so I pull it out and clean it off in some water I've pulled from the tank.

I feel sure your cycle hasn't crashed. You are seeing some ammonia because the bacteria is struggling to eat it with the pH this low. Get you pH back up and I feel sure your ammonia will quickly drop back down to zero.

 

As far as nitrates, you probably need to up the amount of water change at a single time. Check your source nitrates also.

 

My tank has gravel but i do use root tabs for the plants.
In general everything seems to be falling apart.. the plants don't seem healthy, the water readings are bad.
I am at wits end.

I was having this same issue when I decided to replace my silk and plastic plants with real ones. Although I added roots tabs and was using an all in one liquid fert my plants were struggling. I bought a simple little TDS (total dissolved solids) meter. I found out my tap water was missing most of the minerals needed. The TDS of my tap water is 21. Some folks say that is close to RO water. RO water is water almost everything has been stripped from.

I now add enough Equilibrium to get my TDS up to about 100. My plants are thanking me now that they are getting more of what they need. Your tap water sounds a lot like mine although my pH isn't as low as yours. Mine comes out of the tap at 7.2 but would start dropping in the tank. The crushed coral holds it at a steady 7.2

 

You may need to add more CC. Have you pulled it out and cleaned it? If not you may want to do so. I use CC to stabilize my pH. I check the pH from time to time. When it starts dropping I know it is time to either clean or add more. I use the chunks of coral. It is in a media bag in my HOB filter. Once a month or so I pull it out and clean it off in some water I've pulled from the tank.

I feel sure your cycle hasn't crashed. You are seeing some ammonia because the bacteria is struggling to eat it with the pH this low. Get you pH back up and I feel sure your ammonia will quickly drop back down to zero.

i never knew I had to clean crushed corals. Sounds stupid now that i think about it. Will do this ASAP.

As far as nitrates, you probably need to up the amount of water change at a single time. Check your source nitrates also.

Im afraid to change too much of water in one go incase it shocks the fishes in the tank. I heard Neons are very sensitive...

I was having this same issue when I decided to replace my silk and plastic plants with real ones. Although I added roots tabs and was using an all in one liquid fert my plants were struggling. I bought a simple little TDS (total dissolved solids) meter. I found out my tap water was missing most of the minerals needed. The TDS of my tap water is 21. Some folks say that is close to RO water. RO water is water almost everything has been stripped from.

I now add enough Equilibrium to get my TDS up to about 100. My plants are thanking me now that they are getting more of what they need. Your tap water sounds a lot like mine although my pH isn't as low as yours. Mine comes out of the tap at 7.2 but would start dropping in the tank. The crushed coral holds it at a steady 7.2

My tank ph comes out as 7 and then gradually drops. Hence why i have the crushed corals. I do have a TDS meter and my reading is usually below 200. Yesterday my reading was 118 which I have read is okay for a freshwater tank.

 

i never knew I had to clean crushed corals. Sounds stupid now that i think about it. Will do this ASAP.

Cleaning the CC off from time to time removes some of the bio-film that accumulates on it and prevents it from dissolving as well as it should.

Im afraid to change too much of water in one go incase it shocks the fishes in the tank. I heard Neons are very sensitive...

As long as you both temp match and add your water conditioner to the fresh water before pouring it in the tank, large water changes shouldn't affect your fish. I also have neon tetras in my biggest tank. I change out 50% of the water each week. Your fish will get used to the big water changes. Giving them fresh clean water ids the very best way to keep your fish healthy.

My tank ph comes out as 7 and then gradually drops. Hence why i have the crushed corals. I do have a TDS meter and my reading is usually below 200. Yesterday my reading was 118 which I have read is okay for a freshwater tank.

What is the TDS number coming from the tap? The TDS numbers are one thing lots of folks don't keep an eye on. They see a low nitrate number and think they don't need to do a water change but there are other reasons for doing water changes.

118 is a good number. Mine never got that high before I started adding the Equilibrium. Lack of minerals may not be the reason your plants are struggling. In my case it was.

 

Cleaning the CC off from time to time removes some of the bio-film that accumulates on it and prevents it from dissolving as well as it should.


As long as you both temp match and add your water conditioner to the fresh water before pouring it in the tank, large water changes shouldn't affect your fish. I also have neon tetras in my biggest tank. I change out 50% of the water each week. Your fish will get used to the big water changes. Giving them fresh clean water ids the very best way to keep your fish healthy.


What is the TDS number coming from the tap? The TDS numbers are one thing lots of folks don't keep an eye on. They see a low nitrate number and think they don't need to do a water change but there are other reasons for doing water changes.

118 is a good number. Mine never got that high before I started adding the Equilibrium. Lack of minerals may not be the reason your plants are struggling. In my case it was.

I just tested the waters and at this moment the tank is 128 and the tap is 52.

 

I just tested the waters and at this moment the tank is 128 and the tap is 52.

How often were you doing water changes before all of this started? How much do you normally change? I don't know if the problem with your plants is lack of minerals. And of course I can't know what makes up the TDS number in your tank. I have to think it isn't something your plants are using. If it was they wouldn't be going up from the original 52 from the tap all the way up to an occasional close to 200.

To be perfectly honest though. I really don't know enough about this to be giving advice on it. I just wanted to point out what it took to get my plants to start growing and looking healthy for me.

 

Do you feed frozen blood worms? If so you may want to try thawing and rinsing then before feeding

 

How often were you doing water changes before all of this started? How much do you normally change? I don't know if the problem with your plants is lack of minerals. And of course I can't know what makes up the TDS number in your tank. I have to think it isn't something your plants are using. If it was they wouldn't be going up from the original 52 from the tap all the way up to an occasional close to 200.

To be perfectly honest though. I really don't know enough about this to be giving advice on it. I just wanted to point out what it took to get my plants to start growing and looking healthy for me.

My water change regime was twice a week with approx 25% to 30% each time.
Now I have been doing 15% to 20% daily.

Do you feed frozen blood worms? If so you may want to try thawing and rinsing then before feeding

Yes.. I thaw them and rinse them with tank water before feeding

 

Do you feed frozen blood worms? If so you may want to try thawing and rinsing then before feeding

Why are you rinsing them?

 

To remove

Why are you rinsing them?

Bacteria and any unwanted things that might be in the water.

 

My water change regime was twice a week with approx 25% to 30% each time.
Now I have been doing 15% to 20% daily.

Rinse your crushed coral and add more as needed to keep your pH up to at least 7. Instead of doing 2 water changes a week do one 50% water change once a week. Stop doing the daily water changes. Give your bacteria time to do its job. It is possible to keep our tanks too clean. We can keep them looking clean but we don't want to deep clean them.

There should be no way for your nitrates to be this high while doing so many water changes unless you have nitrates in your source water or they are coming from the ferts you are adding. The Thrive I occasionally use shoots my nitrates up to an uncomfortable level. The Jobe's plant spikes I am experimenting with do so too.

Have you run the nitrate test on your tap water to see if that is where they are coming from? It is not a bad idea to run all the tests on your tap water from time to time to see if anything has changed.

 

Thats whats confusing me. My nitrates are super high.
My tap water has no nitrates when i tested them a week ago. I will test them again tomorrow..

I use Seachem root tabs. Is there anything i can do if thats whats releasing nitrates in my tank?

Im just a bit worried on the levels. I have been testing daily and the levels are always high.. afraid they might affect my fishes.
I do have plants and i try my best to vacuum the gravel and remove as much dead plants but certain areas are very heavily planted and I am not sure how to clean them without uprooting the plants.

I have upgraded my lights to help with the plant growth and am looking at getting co2 as well but thats not for another month or two.

I will follow your advice and clean 50% weekly. Meanwhile I will dose prime daily just in case to keep the fish safe. Will that be okay?

 

Thats whats confusing me. My nitrates are super high.
My tap water has no nitrates when i tested them a week ago. I will test them again tomorrow..

I use Seachem root tabs. Is there anything i can do if thats whats releasing nitrates in my tank?

Im just a bit worried on the levels. I have been testing daily and the levels are always high.. afraid they might affect my fishes.
I do have plants and i try my best to vacuum the gravel and remove as much dead plants but certain areas are very heavily planted and I am not sure how to clean them without uprooting the plants.

I have upgraded my lights to help with the plant growth and am looking at getting co2 as well but thats not for another month or two.

I will follow your advice and clean 50% weekly. Meanwhile I will dose prime daily just in case to keep the fish safe. Will that be okay?

To be perfectly honest I think you are seeing a problem when there really isn't one that can't be easily fixed. Once cleaned off and possibly more CC added your pH should go back up where it needs to be. Once it does your bacteria will get back to work clearing out the ammonia.

40ppm nitrates isn't actually something you need to be overly concerned about. They would have to go much much higher than that to hurt your fish. I know it has been said that we must keep our nitrates down to negligible levels but I would not be stressing over 40.

Your plants need food so nitrates higher than you are comfortable with may be something you will have to accept. Once your plants start growing they should help keep the level down. If you are really concerned with them get some nitra-zorb. Run it in your filter and it will pull the nitrate out of there.

What is your reason for wanting to add prime daily? Personally the only time I would be adding it is when I do a water change. Like I said before, give your bacteria a chance to do its job.

 

Im having ammonia in my water. Like 0.5ppm for the past 2 days. I have been using prime to help with this...

I will add more CC to my tank as well.

Thanks for the advice!

 

Im having ammonia in my water. Like 0.5ppm for the past 2 days. I have been using prime to help with this...

I will add more CC to my tank as well.

Thanks for the advice!

Gotcha. Some folks use it thinking it will do something about nitrates. Once the CC gets your pH back up, you stop doing so many water changes and stop cleaning the gravel so much I feel sure your bacteria will get back to work.

 

To remove

Bacteria and any unwanted things that might be in the water.

Also the water gunk they’re frozen in can be high in phosphates according to some people.

I’ve never had an issue with this but, I have a ridiculously heavily planted under stocked 55g tank and only feed blood worms a couple times a week. Water volume helps mitigate that sort of issue

 

Also the water gunk they’re frozen in can be high in phosphates according to some people.

I’ve never had an issue with this but, I have a ridiculously heavily planted under stocked 55g tank and only feed blood worms a couple times a week. Water volume helps mitigate that sort of issue

When I feed worms, I let the worms live in freshwater for 3 days before feeding them, to make sure anything unwanted is 'rinsed' out too. After getting infect some years ago, never taking a wild chance again without precaution.