The Economics of Prophecy

"That's it already on the fifth day... Is this tougher than I expected?"

I checked the tank first thing in the morning, and I glanced at the sight in front of me.

By the way, the cubic tank is the fruit of a demonic conductor mold made by Noel. The high-heat, non-deforming Demonic Gold was ideal for glazing. Thanks to this, we have a high sense of frameless immersion.

Even so, the glass is thicker than it was in the previous life, and it is cubed so that the load caused by the water pressure is even. And heavy, of course. Size about five liters at most.

The little fish, who celebrated their fifth morning in that little tank, "Let Me Go," were clearly losing their energy. One individual flips up and down the belly to swim, and one individual busily travels up and down the tank. Something that moves only the scythe weakly on the gravel laid on the bottom, and some individuals can't even do that.

"You're losing your energy. What's causing this?

When I suddenly thought I had such a voice, Mathier peered over my shoulder. Today is a loose piece with a shoulder. I think it suits you, but when you get approached prioritizing curiosity with that... Rather a defenseless minute, it's highly irritating for this one.

"The most suspicious thing to do is water quality..."

I concentrated my consciousness on the underwater world in front of me. For fish, water is the world itself. Possible elements as basic water quality include oxygen concentration, paehr. And all kinds of minerals, or water hardness, etc.

"The water uses the pond's as it is, and if you don't have enough dissolved oxygen concentration, you can gather it up there."

I barely saw an individual who was staying healthy. The closer the oxygen is to the water surface, the higher the oxygen concentration is than what dissolves in water from the air. If there's not enough oxygen, the fish should gather near the water.

"Paher next, though."

I draped water from my tank in a rainbow finely chopped rectangle I brought from Central Garden. Vinaldia asked me to dye it, a dye sensitive to all kinds of water quality. As far as I can tell, there is no change in colour with the first day. I'm not comfortable with it compared to the water quality test pills of my previous life, but it doesn't seem like there will be any significant change in paher, hardness, etc.

Of course, minerals such as magnesium and calcium are concentrated because the water evaporates. But it won't be there in five days on the boulder.

He maintained it for nearly six months with just enough water, such as a tank in a college semi in his previous life.

"I'm sure there's not enough food."

Maityle said as she turned her nose to the smell of bread drifting from the kitchen.

"... bait is likely to cause it, but maybe the other way around."

My words made me look like I didn't understand Mathilde.

"I think the bait, precisely the resulting excrement, stained the water. First, the tank is much more individual dense than the pond"

It puts ten individuals in just about five litres of water. That is, two per litre. Considering that one size says half the medallion, it's not much as a aquarium tank.

But it's super dense compared to the natural environment. Although the only living thing in there is fish, it would be more than ten times more biodense than that pond. On top of that, in the natural environment the water circulates, but the tank is fixed.

"If you keep your livestock too dense, you'll get sick, so you'll see."

Mayteer looked at the bottom of the tank. There are, of course, a few small, elongated things falling down there. I think it would be a hall as a conversation for a female student, but Mathier doesn't care at all. This kind of place really helps as a co-researcher.

"No, the most important thing is not the visible. Uh, the other one, in human senses."

"Oh, to..."

"I'll keep explaining. Well, first of all, the end of the bait that the fish drains is poison. So I dump it outside..."

I'll be more concerned.

It eats and digests and drains more than it is a creature. Ammonia, the degradation product of amino acids, is highly toxic among the substances emitted from the body of fish. In humans, it turns into a relatively harmless urea and concentrates. Including birds, horse dragons, dragons, etc. Otherwise, it is uric acid and expelled. It's that white one from bird shit.

Ammonia dissolves in water, its format evolved because terrestrial organisms do not want to discard precious water in their bodies at the same time as they discharge ammonia.

Well, the fish live in the water. There are exceptions such as (12), but many fish release into the water while remaining ammonia. If the biodensity is low and the natural environment in which water circulates, that's fine. However, ammonia concentrations increase in the tank, resulting in concentrations where fish cannot live.

"Now that we're talking about it, why don't we change the water in the tank and clean the shit out of the bottom?

"Well, that's one way. It takes a lot of work for humans to take care of, and cleaning itself becomes a burden for fish as a change in the environment. Most importantly, it's counterproductive for my purpose."

Assuming half the water is changed every day, the ammonia concentration will be half. Or I'll sink charcoal or something in the water. Adsorb harmful substances into charcoal. ”Physical” filtration if a word from a previous life. But that's laborious and costly. That is the only aristocrats and large rich people who can paste their servants can enjoy the Aquarium.

"If I don't change the water, I'll accumulate the poison that says its ammonia. Changing the water hates the owner and the fish..."

Maityle shakes her neck.

"In fact, we can make the tank itself have a mechanism to purify that poison. No, that's exactly what's happening right now."

"You're out. Invisible knowledge. Let me tell you how it works."

Mathier's eyes lit up.

"Oh, what the organism produces can be handled by the organism."

It's called ”biological” filtration. Filtration is the removal of certain substances from the liquid, but in this case the nuances are slightly different. It's the same thing that reduces the ammonia you want to exclude from the water, but you take another form instead of removing it.

The principles themselves are also found in textbooks on science in previous life. Use nitrogen circulation. For example, when an animal dies, both on land and in water, the protein rots and ammonia can be done. But neither soil nor water is poisonous. Because it has a mechanism that turns ammonia into nitrite and nitrite into nitric acid with the power of bacteria.

In fact, even in this tank, the ammonia emitted by the fish is starting to be treated little by little. However, I just can't make it because the ammonia increase speed is faster than the processing speed in this state. That's the next stage.

"What's going on with the tank I left to Maytil?

"You mean an empty tank? It's going well. There's nothing in there but gravel and bait. It's waving water vain."

The same thing can be done in the tank. We already have a device for this purpose. That's the screw I asked Maityle for and the gravel I laid on the bottom.

The tank I had left to Maitir lays thick gravel, and the example castle hammer technique is carved into a magic guide, and a tube with a screw structure inside is penetrated. At each rotation, the cylinder sucks up water from the bottom of the gravel layer and releases it to the top of the tank. In other words, the water in the tank circulates through the gravel.

"This gravel and screw matter. I can multiply my ability as a water tank purifier by dozens of times with these two."

bacteria, in this case nitrite and nitrate bacteria, but these propagate by sticking to the surface of the object. A tank with only water has only a bottom and a wall surface, but if you lay gravel on the bottom and circulate water in between, the surface portion of gravel, the surface area, is tens of times greater. With the bait rotted and ammonia generated, large quantities of bacteria reproduce on the surface of the gravel when water is circulated there.

I pinched up a grain of gravel in the water. Thanks to the use of pond water, the surface is already dry. This is the biomorph, the layer of bacteria.

"Hey, let me touch you, too"

Mathier took gravel from my finger. He moves his fingers and says, "I do sweat it."

"Hey, we need to be careful"

I accidentally grabbed Mathier's wrist.

"Kick, suddenly what!?

"No, look, the clothes are dirty."

When I let go of my hand, I pointed to a droplet that was about to spill out of Mathier's palm.

"Oh, yeah. Thanks."

Mayteer slowly returned the gravel to the tank. And I wiped the water dripping down my wrist with the cloth I gave him. The cheeks are a little red.

"We'll keep talking. First, more mucus feed on ammonia released by fish, changing ammonia to say nitrite. Next, the mucus feeding on that nitrite turns nitrite into nitric acid. Nitric acid is considerably less toxic than ammonia. That's how it works."

"... I mean, you're talking about the extremely small mucus in the example. You mean how animal manure and corpses go back to the dirt. Shit, could it also involve fertilizers or something?

Mathier showed understanding. "This is it if you're a little alarmed," he says.

One way or the other, that's our line.

Though the use of livestock manure is also used in this world, I'm more scared in a sense of Mathier noticing that much in the current description. No, you should say you're reliable. At any rate, another purpose of this product is….

◇ ◇

"You've been here a week and you're fine."

"Looks like biofiltration's up and running."

Fish are swimming fine in the tank. It is added from the pond to make it 1.5 times more biodense than it was before. I guess the fact that I used pond water, the gravel was from the creek, made me rise fast.

"Besides, when you have gravel, it feels like it's in the river. It's a little weird watching that from the side. Does that mean you don't need a water change now?

"No, fish excrement just took on a less harmful form, and it wasn't lost out of the water. Problems arise in the long run. I need a minimum water change. However, the frequency of water changes can be considerably reduced. Maybe, but once a week, if you swap about a fifth of the amount, you can keep it."

Nitric acid is a lot less toxic than ammonia, but it's the same that accumulating too much in the water can be harmful. Ultimately, the accumulated nitric acid hunts down the fish. Actually, there are some ways to get nitric acid back to nitrogen molecules, or gases, to be completely harmless, but that's difficult because we need anaerobic conditions.

"Hit one more hand. I have to do with what Mathilde just said."

"What I said?

"Oh. Add what's in the tank. I'm just sorry before that..."

I saw a metal cylinder serving as a simple pump. Smaller solids are rushing to redirect towards water momentum as they approach.

"Enough for water to pass through the gravel, and gentle for fish. That's how much output you have to adjust."

Mayteer took out a spare barrel of magic gold.

"That'll help."

"Leave it to me. I'll adjust as soon as I can. I'm wondering what Ricardo's gonna do next."

Maityle said as she wrapped her arms around the costume of the blame.