Accidental fish in cycle - help please.

[LadyDay]

Hi guys.
So, 5 weeks ago I started an 80 Liter aquarium, using Tropica Soil as substrate. I then got the expected Ammonia spike first, then a Nitrite spike. After 4 weeks it had tested free from Ammonia several weeks and free from Nitrite for a few days, so I added the first fish. Two young (not adult size) Lyretail Killi. Everything went by the book and the fish acted normal and healthy. Then today, four days later, since the two Killi were still apparently healthy and happy, I did a big water change, stupidly not testing the water since the fish didn't indicate anything wrong, then added 12 Microdevario kubotai, after acclimatising them carefully (drip). To my surprise the new fish seemed very lethargic, not handling the current in the water and most of them hiding. So I tested the water again and to my horror it showed Nitrite! 0.3 mg/L, so not dramatic amounts, but still. So now I'm apparently cycling an aquarium with fish in it! I immediately did a big (about 70%) water change of course. But now what? How much water do I change and how frequently until the tank is done cycling and handling the number of fish?
The tank is pretty densely planted (including floating plants), but has an algae problem (diatom), which I figure is normal in such a new tank.
Thanks for any advice!

 

[LadyDay]

Picture of the tank

 

[John q]

So now I'm apparently cycling an aquarium with fish in it!

It happens, change 50% of the water daily, and stop beating yourself up about it.

 

[LadyDay]

It happens, change 50% of the water daily, and stop beating yourself up about it.

Thank you for the encouragement, I will stop beating myself up and hopefully the water changes will prevent any disaster.

 

[_Maq_]

Hydrogen peroxide oxidizes nitrites to nitrates rapidly. According to the books. I've never had to check it myself.

 

[LadyDay]

An update: This morning the water is testing free of Nitrite (and Ammonia) and the fish are looking much better, swimming about being fish, not lethargic and not getting overwhelmed by the flow. I will still do the water changes, it can't hurt, and closely monitor the water parameters.

@_Maq_ That sounds interesting. I do have a bottle of it which I can use in case of emergency. Will have a closer look into it. It wasn't loads and loads of Nitrite in the water, and the water is testing free now, so hopefully drastic measures won't be needed, but it's good to have at hand!

 

[Hanuman]

@_Maq_ That sounds interesting. I do have a bottle of it which I can use in case of emergency. Will have a closer look into it. It wasn't loads and loads of Nitrite in the water, and the water is testing free now, so hopefully drastic measures won't be needed, but it's good to have at hand!

Be very careful when dosing H2O2. It is a strong oxydizer and could have the opposite effect by stressing or even killing the inhabitants. I strongly suggest you don’t use H2O2 for nitrite reducing purposes. It might be effective but there are much much safer methods like changing water or simply dosing a water conditionner temporarily.

 

[LadyDay]

Be very careful when dosing H2O2. It is a strong oxydizer and could have the opposite effect by stressing or even killing the inhabitants. I strongly suggest you don’t use H2O2 for nitrite reducing purposes. It might be effective but there are much much safer methods like changing water or simply dosing a water conditionner temporarily.

I am indeed thinking it sounds like an extreme measure! And I think water changes will do the trick. Hopefully the beneficial bacteria culture will establish soon.

 

[_Maq_]

Be very careful when dosing H2O2.

Hydrogen peroxide is a dangerous substance, of course.
I've tried to make some calculations, though. Let's say, there's 1.0 mg/L nitrites in the tank. To oxidize this amount, you need 25 mg/L H2O2 3% solution. That amounts to 2.5 gram per 100-liter tank. Such an amount is absolutely safe.
The big question, though, is what share of this tiny amount would actually react with nitrites? Nitrite is one of the strongest reducing agents present in aquarium, so that we may suppose that affinity between peroxide and nitrite would be high. Still, this remains a big unknown given that there's no way to arrive at reliable estimate for something as diverse as an aquarium.
Still, 10 ml H2O2 3 % sol. per 100 L tank is pretty safe and can help. Even if it does not oxidize exactly nitrites, it will oxidize something, decreasing high oxygen demand. And too high oxygen demand is the cause of nitrites proliferation.

An absolutely safe (yet not absolutely efficient) way to get rid of nitrites is aeration. And water changes, of course.

 

[LadyDay]

Hydrogen peroxide is a dangerous substance, of course.
I've tried to make some calculations, though. Let's say, there's 1.0 mg/L nitrites in the tank. To oxidize this amount, you need 25 mg/L H2O2 3% solution. That amounts to 2.5 gram per 100-liter tank. Such an amount is absolutely safe.
The big question, though, is what share of this tiny amount would actually react with nitrites? Nitrite is one of the strongest reducing agents present in aquarium, so that we may suppose that affinity between peroxide and nitrite would be high. Still, this remains a big unknown given that there's no way to arrive at reliable estimate for something as diverse as an aquarium.
Still, 10 ml H2O2 3 % sol. per 100 L tank is pretty safe and can help. Even if it does not oxidize exactly nitrites, it will oxidize something, decreasing high oxygen demand. And too high oxygen demand is the cause of nitrites proliferation.

An absolutely safe (yet not absolutely efficient) way to get rid of nitrites is aeration. And water changes, of course.

But the Hydrogen Peroxide would be a temporary solution anyway right? Since the bacterial culture still isn't there to do the job of converting to Nitrate.

I just tested the water and sure enough, there's a bit of Nitrite again. Frustrating! I don't know if I should do a second water change today or wait until tomorrow? Can I change too much water?

 

[dw1305]

Hi all,

Can I change too much water?

No not really.

cheers Darrel

 

[LadyDay]

No not really.

Super. I'll get right on with it!

 

[_Maq_]

But the Hydrogen Peroxide would be a temporary solution anyway right? Since the bacterial culture still isn't there to do the job of converting to Nitrate.

That's one possibility. Another possibility is that bacteria are present but suffer from unfavourable conditions. Nitrification is a great scavenger of oxygen, so adding oxygen helps a lot. Aeration is safe. H2O2 is a temporal measure in times of trouble.

 

[LadyDay]

That's one possibility. Another possibility is that bacteria are present but suffer from unfavourable conditions. Nitrification is a great scavenger of oxygen, so adding oxygen helps a lot. Aeration is safe. H2O2 is a temporal measure in times of trouble.

How do I best increase aeration? I have a lot of surface agitation. I could add an air bubbler, but am worried that might remove a lot of the injected CO2, thereby limiting plant growth. The CO2 is on from two hours before lights on until lights off. I could in principle turn off CO2 entirely until the tank is fully cycled and stable, to increase the oxygen available to the fish, but am worried about what that will do to the plants. The plants also produce oxygen during light hours when growing well. I have quite a lot of diatom algae still and would therefor be sorry to slow down plant growth, since I want to get rid of the algae obviously. The algae is also causing damage to the plants. I just removed a lot of dead plant matter yesterday that I found in between the plants, which I expect has been contributing to the Nitrite problem.
How do you suggest I proceed? I want to give the tank and fish all the Oxygen they need.

 

[_Maq_]

However I am hesitant because the old tank is plagued by BBA

I think that there's little reason to worry. Algae spores are omnipresent, so algae outbreak is not a function of inoculation but favourable conditions.

How do I best increase aeration? I have a lot of surface agitation. I could add an air bubbler, but am worried that might remove a lot of the injected CO2, thereby limiting plant growth.

You know, I'm a hardcore low-tech. Never ever injecting CO2. But I aerate permanently, by water pump with venturi. That's my choice, but surface agitation or other ways may be just as efficient.
You say you're removing a lot of dead plant matter. I'll speak for myself, many think differently: Your plants currently need oxygen more than carbon dioxide. Keep in mind that all living creatures need to respire just as humans. You may stay hungry for a few days, but without oxygen, you're dead within minutes.
It's up to you. Like I said, I'm a hardcore low-tech and oxygen obsessed.

 

[Hanuman]

It happens, change 50% of the water daily, and stop beating yourself up about it.

How do I best increase aeration? I have a lot of surface agitation.

Stop beating yourself. Changing water or adding some water conditioner is by far the best things to do. Forget about H2O2. If you have a lot of surface agitation that will be enough to oxygenate the tank. Simply keep an eye on the fish.

I could in principle turn off CO2 entirely until the tank is fully cycled and stable, to increase the oxygen available to the fish, but am worried about what that will do to the plants.

I don't recommend doing that. Also CO2 and O2 are not mutually exclusive. As long as your tank is properly oxygenated and CO2 levels are not in a deadly zone fish will be fine. If you start depriving plants from CO2 while they were used to it you will have additional problems to deal with as their health will be impacted temporarily. Not something you want now.

I have quite a lot of diatom algae still and would therefor be sorry to slow down plant growth, since I want to get rid of the algae obviously.

Leave the diatoms alone. They will disappear eventually. If you have snails in there they will eat it faster.

Another thing. I am considering taking some filter gunk from my old aquarium and adding it to the filter in the new tank. However I am hesitant because the old tank is plagued by BBA, which I'd hate to transfer to the new tank, it's a nightmare to get rid of again! Should I be worried about infesting the new tank by using filter media from the old tank?

At this point that's no necessary. Let the cycle finish its course.

 

[LadyDay]

@_Maq_ and @Hanuman , I am now thoroughly confused, getting two opposing messages. I suspect that's because there are different approaches to aquarium keeping. I have no idea which way to go in my specific case.
I didn't have Nitrite this morning (but I still changed 50% water), I will test the water again in the afternoon.
I am hesitant to make too many changes while the tank is trying to cycle and mature, if I can keep the Nitrite away by water changes, patience is a virtue after all, but I do of course want to make sure my poor fish and plants aren't slowly suffocating by reoccuring Nitrite issues and lack of Oxygen!

 

[Hanuman]

@_Maq_ and @Hanuman , I am now thoroughly confused, getting two opposing messages. I suspect that's because there are different approaches to aquarium keeping. I have no idea which way to go in my specific case.

Not sure were it is opposing other than the CO2 part. If you stop CO2 at this point, plants will have to reconfigure themselves, so to say, to adapt to new conditions with less CO2. That usually impacts the plant. Unless you are injecting CO2 to the point where fish as gasping, there is absolutely no reason to stop it. You added it for a good reason, so stick to that. Also as I said CO2 and O2 are not mutually exclusive. You can have both in the water at the same time. What you don't want is to deprive the tank of oxygen. That would be letal to everything. Fish, plants and bacteria.

I didn't have Nitrite this morning (but I still changed 50% water), I will test the water again in the afternoon.

Well you are on the right path then. Maybe wait 2 days and test again see if nitrite is going up. If not, then you can start spacing water changes.

I am hesitant to make too many changes while the tank is trying to cycle and mature,

No not really.

Darrel answered that. Your bacteria is in your susbtrate, plants and filter. Not really in the water column. If the water you are changing is identical in terms of parameters than the water in the tank, then there is no harm. In fact it's the opposite as you are removing dissolved organics when changing water so it's quite beneficial to the tank.

 

[LadyDay]

I can't figure out how to do the multiple quotes in one post.
Anyway, @Hanuman I was unclear. By saying I am hesitant to make too many changes I didn't mean that I'm hesitant to make water changes, I keep changing lots of water daily, I meant that I'm hesitant to turn off CO2. I think I agree with you that it should stay on (it's not at a level that's effecting the fish - the drop checker goes a "dark lime green" and the fish aren't gasping or seeking to the surface). I don't know if I should do anything additional to keep Oxygen levels high at the same time, since I have good surface agitation.
Your suggestion of testing again in two days to see if Nitrite goes up sounds like a good plan.
I so appreciate the help!

 

[John q]

I didn't have Nitrite this morning (but I still changed 50% water), I will test the water again in the afternoon.

I don't know if I should do anything additional to keep Oxygen levels high at the same time, since I have good surface agitation.

Noon can say for certain but if you are doing daily water changes, have good surface agitation and have decent flow around the tank I'd suggest you will have adequate levels of oxygen in the tank.

On a side note what temperature are you running the tank at?