How much elemental gaseous Nitrogen is dissolved in our tanks?

[B7gwap]

Hey everyone

I have been fiddling with low tech CO2 in my 75 gallon planted and my son’s 20L planted tanks, having fun and remembering bits from my college chemistry classes. 
 

I built a little 2L soda bottle yeast reactor and have been using ACO’s Zia’s air stones as diffusers. I was reading about upside down bell diffusers and how the surface area of the bubble-to-water interface is where the gas is dissolved into the water. 
 

It’s fun, and since it won’t crank out as much gas as a pressurized system I haven’t seen any I’ll effects on my critters, and the plants seem to appreciate it. 
 

I was thinking back to Physics and that the elemental mixture of gases in the atmosphere is 70 something N2, 21 or so O2, and CO2 and other stuff is less than 1.5% or so. Everything I search for about dissolved Nitrogen gas in aquarium water turns up helpful articles about Nitrogen compounds like NO3 and NO4, but what about the simple dissolution of elemental nitrogen gas in our water since it’s so abundant in the air? Does it interact with our plants or animals?

Here to learn. 🙂

Austin

[Scapexghost]

Nitrogen is a very stable gas, so very few organisms can interact with it

[B7gwap]

That’s a good point. So, probably well represented in the solution but non-interactive. That’s what gives scuba divers the bends, right? High pressure N2 dissolved in their blood coming out of solution and bubbling?

Dissolved N2 is probably where the bacteria get the Nitrogen for Nitrites and Nitrite imagine. Well, I guess there’s the NH4 from the fish waste too. Is that N from the water column or their food has it maybe. 

[Scapexghost]

On 11/27/2021 at 11:00 PM, B7gwap said:

That’s a good point. So, probably well represented in the solution but non-interactive. That’s what gives scuba divers the bends, right? High pressure N2 dissolved in their blood coming out of solution and bubbling?

Dissolved N2 is probably where the bacteria get the Nitrogen for Nitrites and Nitrite imagine. Well, I guess there’s the NH4 from the fish waste too. Is that N from the water column or their food has it maybe. 

The bacteria in aquariums get nitrogen from ammonia and nitrite. Most forms of bacteria that can utilize nitrogen cannot do so in an ordinary aquarium.

[Minanora]

I know this is not helpful surrounding nitrogen... But. Sweet! I never thought to use yeast. I'm assuming you get CO2 generation for about 2 weeks.

Now I'm thinking about reusing my higher tolerance wine yeasts for my fish tank CO2...

I see what look like inline filters on your lines. Did you ever have any issues with it getting too warm and getting krausen(foam) into the airline you're using?

I bet I could make Mead next to my 75G! 😂

 

Yup, going to make Mead next to the aquarium, for science.

Edited November 28, 2021 by Minanora
Added context

[B7gwap]

Yes, PLEASE make mead while you do fish stuff! And then share the recipe. 
 

What looks like an inline filter is actually a check valve to prevent back flow and to allow easy change out of bottles without losing all your pressure. 
 

Been using 2 cups sugar, one packet of yeast, one tap baking soda, and it can last for two weeks or so, yes. 
 

I’m also running a test batch of Jello with one added cup of sugar to the gelatin, then yeast on top, going on three weeks at a slower injection rate there.

You guessed it, if you mix the first mixture too warm, it will foam, and if it’s close to the top of the bottle… you will make a mess in your tank. Many folks run their output through a straw inside a second bottle with plain water at the bottom, then a gas-only output at the top. Kind of a water filter cell. I haven’t tried this yet but 2 liter soda bottles are 88 cents at Wally World, so maybe I will on the next one.

Thoughts so far? Not sure it’s putting enough in to really matter, the plants seem happy but that could be the easy green and controlled 10-hour light schedule.  But potentially being not enough to matter also means it’s not enough to be dangerous, so that’s a benefit.  Hard to argue with the price of the setup.  
 

Don’t use a ceramic diffuser with this setup, I have done it, and it works, but the fine airborne particulates from the yeast reaction can clog the very fine pores, and when you get high enough back pressure, something will fail. In my case it was a makeshift silicone bulkhead in the lid of one of my soda bottles.  Let’s say my wife was something other than pleased at the improbable range and coverage of sugar water from such an eruption. “THE WHOLE HOUSE SMELLS LIKE BREAD AND OR BEER!”

Also not all check valves are designed to take that kind of back pressure, I had one from ACO fail, it shoved the little rubber insert up against the downstream side of the housing and turned it from check valve into a plug in both directions.

I really like this hobby, it’s fun to tinker and apply so many sciences inside of what is essentially an art form. I’m glad my wife likes me and lets me and the kids have fun with it. 🙂

 

[B7gwap]

On 11/27/2021 at 11:33 PM, Scapexghost said:

The bacteria in aquariums get nitrogen from ammonia and nitrite. Most forms of bacteria that can utilize nitrogen cannot do so in an ordinary aquarium.

Right, I guess I’m wondering where the fish get the nitrogen that is bound up in ammonia in the first place. Food? Respiration? 

[Minanora]

On 11/28/2021 at 9:05 AM, B7gwap said:

my wife was something other than pleased at the improbable range and coverage of sugar water from such an eruption. “THE WHOLE HOUSE SMELLS LIKE BREAD AND OR BEER!”

I laughed so hard at this!

On 11/28/2021 at 9:05 AM, B7gwap said:

Also not all check valves are designed to take that kind of back pressure

We brew beer, make wine, meads and run CO2 to kegs in a chest freezer turned "keezer" so I have some check valves that will hold up for this application!

 

On 11/28/2021 at 9:05 AM, B7gwap said:

PLEASE make mead while you do fish stuff! And then share the recipe.

Will do! It stays cold enough this time of year to make it in the living space!

 

Thank you for the detailed notes on your experience. I will definitely be rigging up a carboy next to the 75G soon. Maybe not my sons 20G tall though.... Don't really want his room to smell like booze all the time.

 

Edited to add that the first thing I said to my Husband this morning, while still in bed, was "I've had an epiphany... I'm going to use the CO2 from making booze... to inject CO2 into my fish tank. Genius!" He rolled his eyes at me, nodded, and then I saw the eyebrow raise of acceptance.

Edited November 28, 2021 by Minanora
Added more.

[B7gwap]

Cool!

Yeah, if you’re already making the stuff, talk about a great symbiosis. I’m all about repurposing stuff that would have been wasted. 

The easiest CO2 saturation test I’ve seen is to measure PH before and 2 hrs after you start injecting. Anything more than a full PH point drop could be dangerous, but I’ve never really seen it drop by much using low pressure yeast. If you run low KH tanks already be advised CO2 can screw with your PH and hurt critters. I run my 75 at 6.6 PH and 35-40 ppm KH, my son’s endler tank is 7.6-8.0 PH and 120-160 KH, so it doesn’t care one whit about CO2. 
 

High pressure CO2 people turn it off at night, but I don’t. (As you know Yeast are stubborn negotiators) It just doesn’t put enough in to hurt at night when the plants can’t take it up. I haven’t seen anyone in the tank behave strangely or gasping or shooting to the surface. 
 

Good luck with your rig and keep us posted! 
 

-Austin

[Scapexghost]

On 11/28/2021 at 10:32 AM, B7gwap said:

Right, I guess I’m wondering where the fish get the nitrogen that is bound up in ammonia in the first place. Food? Respiration? 

Fish get nitrogen from protein in fish food