Hello fellow planted tank enthusiasts!

I've recently run into something that has never happened to me before. After doing some research I decided that I wanted to set up a dirted tank. For a low risk setup I decided to use a cheap old 10 gallon tank that I was planning on heavily planting and stocking with a betta.

I used soil from behind my house that I cleaned to the best of my ability, then baked in an oven for a while to kill anything potential pathogens. There are no fertilizers used in this soil. I capped approximately 1/2" of this soil with about 1" of sand. I used thoroughly washed and baked Quikrete play sand. After overflowing the tank outside for a while to get all the floating junk out, I threw everything together and planted everything. I threw on a HOB filter that came straight from one of my other tanks, already cycled and everything. I went and got my betta, and he's doing well.

Now, for my problem: the tank has been running 3 and a half weeks now and my ammonia keeps rising! I'm using a filter that I've used plenty before and it's worked beautifully. I have a consistent reading of ammonia, 0 nitrites, and about 5 ppm nitrates -- which I attribute to my tap water. This makes no sense to me. I can only come up with the idea that something in the sand or dirt must have killed the nitrosomas/nitrosomonas and nitrobacter. Anyone have any idea?



TL;DR - First dirted tank killed a pre-cycled filter and now tank is stalled. Think it's the sand or dirt. Help.

The dirt could be leaching too much ammonia for the bio filter to handle

I initially thought that too, but the lack of nitrates tells me that there isn't any bacterial metabolism happening. If the ammonia was being converted, the nitrates would be going up. I'm fairly certain that I don't have enough plants to take up the nitrates that rapidly.

Your bacterial population is not settled yet, so the ammount of ammonia that it can convert is rather small right now.

Also, if there are plants, they consume ammonium.

Michel.

Yeah, I think I'm leaning quite hard on my plants right now for consumption of ammonium. The thing that makes me question what's going on is that the filter was cycled, and working to support a 20 gallon tank. Now, I know the bacteria population exists in the substrate and other surfaces, but that filter should have been adequate to handle the waste from one betta and some leaching. I'm seeing no increase in nitrates.

When soil is first flooded, it is suddenly exposed to a sudden environment and that creates all kind of new chemical/biochemical reactions. As a result, as pointed out by @sohankpatel ammonia will leach out of the soil.

What's not helping you is also the fact that you "baked" your soil. You wanted to kill pathogens that more than likely never existed while also kill all beneficial bacterias that were already in the soil.

I setup a tank recently using clay dugout of my backyard, pond soil and play sand and did not bake anythinIt took 19 days to cycle the tank without any seeded filter or "magic" bottled solution. The tank is filterless anyway. You can see the link "My alternative aquarium" on my signature.

Sounds like a pond. Haha. I guess I have some reading to do. I knew that baking it would kill more or less everything, but considering that approximately half the beneficial bacteria live in your filter, and I had previously run this filter on a 20 gallon, I figured it'd be close to good to go on the ten. I've swapped out filters to seed new tanks and have gone without any spikes whatsoever, although I did imagine I'd have some fluctuation with the dirt and all.

I think you go on to prove my point that something is wrong. You cycled a filterless, dirted tank from scratch in 19 days. My tank, with a seeded filter has not cycled in much longer than that. I just wish I could figure out what's causing the bacteria to struggle so much.

Bump: I just looked at your "alternative aquarium" and I've got to say that saying you have no filter is a stretch. That pump covered in geotextile with a plastic scrubby in it is a filter if I've ever heard of one. Just because it's not a "water polisher" doesn't mean it's not a filter. Heck, people use those plastic pot scrubbies as cheap bio-material! Cool tank though!

Bah I guess being unheated with terrestrial plants on the side, you could call it an indoor pond LOL.

Quote from the book An Alternative Aquarium - A robuste habitat: "Should you boil the dirt? Only if you intend to eat it".

I agree, saying I have no filter is a bit of a stretch. But it's main role is to prevent the snails from being sucked in. I used this little pump before by itself and small snails would always plug the inlet. At 70 gpm, it's not much of a filter . If I had a small wire mesh that would be even better. That's the plants' job.

Thanks for the thumbs up.

Bump: The other tank you cycled, how did you treat the substrate?

Haha, I suppose we all have indoor ponds in some way, shape, or form. Yeah, 70 gpm much turnover for a 20g. You make a good point.

My other substrates have been aquasoil and eco-complete, or just plain jane aquarium gravel before I started really planting. I didn't do anything to them other than a quick rinse before I put them in the tank though. (Always with seachem prime, obviously).

I am pretty sure more knowledgeable people will join in. How are the plants doing?

If you ever start this over, I would give it a shot without baking anything. I know... I am so stubborn on this

Aww this is a good one.

1) When you baked the soil this killed the bulk of the little critters in the soil.

2) The the amount of N in the microbial biomass can be large. For example crops need between 150-300lbs/acre of N to grow. The amount of N locked up in the soil microbes can be as much as 130lbs N/acre.

Microbial Biomass | Fact Sheets | soilquality.org.au

3) Depending upon the makeup of the soil and its CEC (cation exchange capacity) the minerals in the soil can lock up even more N. Even if you never fertilized it the nitrogen fixing organisms are slowly adding nitrogen to the soil from the air. This is then locked up into the minerals of the soil.

4) When organic material is decomposing the carbon to nitrogen ratio is very important to understand.

High carbon & low nitrogen means that nitrogen will be deficient until all of the food is broken down then released rapidly when microbes doing the decomposition run out of food and die.

Balanced Carbon and Nitrogen will lead to a more steady release of N during the decomposition process.

Low carbon and high nitrogen will lead to a very fast initial release of N followed by a slower more steady release.

So now what in blue blazes is happening in your tank.

Hypothesis: (Gratuitous scientific word used correctly).

After baking the soil you added it into the tank with the established filter and plants. This inoculated the tank with lots of bacteria, algae, protists, rotifers, fungus, etc. The whole kit and caboodle of microbial aquatic world. These quickly found all of the yummy killed microbes from the baking and quickly started gobbling them up. Since these killed microbes have about the same C:N ratio as the live ones they grew rapidly. However when all of the yummy killed microbes are eaten up, the large population of living microbes start starving. They slowly start to die off and as their corpses are eaten by remaining living ones they steadily release ammonia into the water.

The mineral side of the soil when immersed in water started releasing some of the nitrogen it had locked up. So you likely had a steady amount of ammonia in the tank from the beginning. Likely much more than the filter or plants could readily handle.

Then you popped in your adorable little carnivorous betta. He dines on a premium high protein feed and produces a steady stream of ammonia.

Like a good owner you test your water frequently to ensure your adorable little carnivorous betta has the best conditions. YIKES! Ammonia is there. So you do an immediate water change. The next day you test again. YIKES! more ammonia. Another water change. Repeat for 3 weeks and you are left with low Nitrates and a steady stream of ammonia entering the water.

Between the water changes and hungry hungry hippos of plants you detect the steady incoming stream of NH3 but no real changes to the other ratios.


Solution for next time: Don't add in fish for 3-4 weeks after starting a baked soil substrate.

Ta Da - BTW most hypothesis are proven wrong.....

Bump: No drinking was involved in the previous post but it is a boring Friday afternoon at the office.

Interesting reading/theory, even after a beer. But my head feels so dizzy now not sure if it's the beer or the theory. I never realized that after baking, the living (now dead) matter now becomes an "extra" source of N. Interesting. I guess I never realized it because I was never interested in baking dirt. lol

Hypothesis NOT Theory. Hypothesis is a logical explanation for an event that is not backed by scientific experimentation. A theory is a hypothesis that is backed by repeated scientific experimentation.

Like anyone cares outside of science.

Yep. It's the Friday beer... that's what I wanted to type. And I can't blaim it on the auto correct.

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You guys are cracking me up.
Yes, I mean @THE V and @Mariostg