How to add CO2 to a fresh water tank

[tonitetra]

Okay so I have a 45 gallon planted tank with some discus. I am about to try and create a moss carpet. I want to add some CO2 to the water for the plants. My plants are growing fine now but I really want them to flourish. So I am wondering what’s the best way to add CO2 and how much do I add? Basically I’m looking for a quick lesson in it. Thanks !!

 

[HoldenOn]

Okay so I have a 45 gallon planted tank with some discus. I am about to try and create a moss carpet. I want to add some CO2 to the water for the plants. My plants are growing fine now but I really want them to flourish. So I am wondering what’s the best way to add CO2 and how much do I add? Basically I’m looking for a quick lesson in it. Thanks !!

Co2 is not recommended for fish tanks if the stocking isn't built around the Co2. I wouldn't recommend it. How many discus do you have in there?

 

[Wills]

I dont think I can put it any better than this video George Farmers videos are really great for setting it up. You should keep an eye on his channel as he is about to set up a planted Discus tank which will likely be a high tech set up

It is important to remember though, you should only use Co2 in conjunction with good lighting and fertilisers as otherwise you wont definitely achieve the growth you want and will risk algae. You also need a high level of plants from the start to convert the Co2 back into oxygen for the fish to breath. You will see in the video but your shopping list should be something like

- Source of Co2 - I use a 2kg Co2 fire extinguisher
- Co2 regulator - I would recommend a Co2 Art dual regulator you will want one with a solenoid which means you can turn the supply on and off electronically
- Bubble counter - this attaches to the regulator and lets you count the number of bubbles of Co2 being released into the tank
- Drop checker and fluid - very important as it shows you what you will need
- Co2 specific air tube
- Co2 diffuser - either inline, which attaches to your filter outlet pipe or diffuser which is a ceramic disk of some kind that goes in the tank
- Airstone and air pump - on a night plants start to use oxygen instead of Co2 so you need to turn the Co2 off and turn the oxygen off to make sure the water is oxygenated enough for the fish through the night.
- Mechanical plug timers - one for Co2 and one for oxygen.

Which plants are you growing at the moment and which ones do you want to grow? You can have a decent level of success without Co2 things just take a bit longer. But in combination with good lighting and fertilisers it is possible to create effective scapes.

It is important to remember that the plants need to come second to the fish too as Co2 mistakes can kill fish.

Wills

 

[tonitetra]

Co2 is not recommended for fish tanks if the stocking isn't built around the Co2. I wouldn't recommend it. How many discus do you have in there?

I have 4 right now and I do plan on getting a larger tank, prolly 75-85 gallon, so I would want a set up that I can also use for when I size up.

 

[HoldenOn]

I have 4 right now and I do plan on getting a larger tank, prolly 75-85 gallon, so I would want a set up that I can also use for when I size up.

Sounds good, 50 gallons is recommended minimum for 1.

 

[tonitetra]

I dont think I can put it any better than this video George Farmers videos are really great for setting it up. You should keep an eye on his channel as he is about to set up a planted Discus tank which will likely be a high tech set up

It is important to remember though, you should only use Co2 in conjunction with good lighting and fertilisers as otherwise you wont definitely achieve the growth you want and will risk algae. You also need a high level of plants from the start to convert the Co2 back into oxygen for the fish to breath. You will see in the video but your shopping list should be something like

- Source of Co2 - I use a 2kg Co2 fire extinguisher
- Co2 regulator - I would recommend a Co2 Art dual regulator you will want one with a solenoid which means you can turn the supply on and off electronically
- Bubble counter - this attaches to the regulator and lets you count the number of bubbles of Co2 being released into the tank
- Drop checker and fluid - very important as it shows you what you will need
- Co2 specific air tube
- Co2 diffuser - either inline, which attaches to your filter outlet pipe or diffuser which is a ceramic disk of some kind that goes in the tank
- Airstone and air pump - on a night plants start to use oxygen instead of Co2 so you need to turn the Co2 off and turn the oxygen off to make sure the water is oxygenated enough for the fish through the night.
- Mechanical plug timers - one for Co2 and one for oxygen.

Which plants are you growing at the moment and which ones do you want to grow? You can have a decent level of success without Co2 things just take a bit longer. But in combination with good lighting and fertilisers it is possible to create effective scapes.

It is important to remember that the plants need to come second to the fish too as Co2 mistakes can kill fish.


Wills

Right now I have two Madagascar lace plants, two anubias , and one amazon sword that isn’t doing to good. I did have an amazing banana plant but it almost died . I have an led light that is on a 24 hour timer and I used seachem root tabs along with seachem flourish. I mean I would love to add more plants but they are so hit or miss in my tank and I need full plants for the discus to hide.

 

[tonitetra]

Sounds good, 50 gallons is recommended minimum for 1.

Minimum of 1 discus for 50 gallon ? I was told it’s about 10 gallons per adult discus. Also, my discus are in an age range of adolescent and juvenile.

 

[HoldenOn]

Minimum of 1 discus for 50 gallon ? I was told it’s about 10 gallons per adult discus. Also, my discus are in an age range of adolescent and juvenile.

You need 50 for the first one at least. Then it's 10 gallons per adult.

 

[StevenF]

- Source of Co2 - I use a 2kg Co2 fire extinguisher
- Co2 regulator - I would recommend a Co2 Art dual regulator you will want one with a solenoid which means you can turn the supply on and off electronically
- Bubble counter - this attaches to the regulator and lets you count the number of bubbles of Co2 being released into the tank
- Drop checker and fluid - very important as it shows you what you will need
- Co2 specific air tube
- Co2 diffuser - either inline, which attaches to your filter outlet pipe or diffuser which is a ceramic disk of some kind that goes in the tank
- Airstone and air pump - on a night plants start to use oxygen instead of Co2 so you need to turn the Co2 off and turn the oxygen off to make sure the water is oxygenated enough for the fish through the night.
- Mechanical plug timers - one for Co2 and one for oxygen.

With the above methode you have periodically check the presures and bubble rate. for various reasons CO2 flow can change unexpectedly and if you get too much in the tank it can kill every fish in the tank.

There i a safer way to do this and it is often referred to as upside down bottle methode. Basically ou put a bottle in the water upside down. And peiodically fill it with CO2. This method completely removes the risk of putting to much CO2 into the tank. It is also much more efficient. I use a 20oz paintball tank as My CO2 container. With a CO2 diffuser I had to refill the container once every 4 months. Now that I have switched to the upside down bottle methode the paintball tank has gone 9 months. I can probably gt about 1 year on a 20oz of CO2. There is no way to put too much CO2 into the water with this methode. Any excess CO2 will come out as one bid bubble and dissipate into the air very rapidly.

 

[Wills]

With the above methode you have periodically check the presures and bubble rate. for various reasons CO2 flow can change unexpectedly and if you get too much in the tank it can kill every fish in the tank.

There i a safer way to do this and it is often referred to as upside down bottle methode. Basically ou put a bottle in the water upside down. And peiodically fill it with CO2. This method completely removes the risk of putting to much CO2 into the tank. It is also much more efficient. I use a 20oz paintball tank as My CO2 container. With a CO2 diffuser I had to refill the container once every 4 months. Now that I have switched to the upside down bottle methode the paintball tank has gone 9 months. I can probably gt about 1 year on a 20oz of CO2. There is no way to put too much CO2 into the water with this methode. Any excess CO2 will come out as one bid bubble and dissipate into the air very rapidly.

that’s really interesting! I’ve heard about this method but never seen it done do you have any pics?

I think the Co2 dump you mentioned is much less likely as long as you use a dual stage regulator so you can control how much Co2 goes into the reg and how much comes out. Then with a bubble counter and drop checker you can see how much what is going on - I just check mine when I look at the tank.

Wills

 

[mbsqw1d]

With the above methode you have periodically check the presures and bubble rate. for various reasons CO2 flow can change unexpectedly and if you get too much in the tank it can kill every fish in the tank.

There i a safer way to do this and it is often referred to as upside down bottle methode. Basically ou put a bottle in the water upside down. And peiodically fill it with CO2. This method completely removes the risk of putting to much CO2 into the tank. It is also much more efficient. I use a 20oz paintball tank as My CO2 container. With a CO2 diffuser I had to refill the container once every 4 months. Now that I have switched to the upside down bottle methode the paintball tank has gone 9 months. I can probably gt about 1 year on a 20oz of CO2. There is no way to put too much CO2 into the water with this methode. Any excess CO2 will come out as one bid bubble and dissipate into the air very rapidly.

I've seen the diffuser aspect set up like that, as in the 'upside down bottle', except it was a bit more posh, more like an acrylic box. Eg https://www.ebay.co.uk/itm/274450155488
But I never questioned how they fill up with co2 without continually overflowing.
Ive been using bicarb+citric acid to make co2 and I think this could be a much better way of making use of the diy method as theres no worry about providing a consistent supply. Just open the valve each morning to fill the bottle
Gonna be giving this a go

 

[StevenF]

that’s really interesting! I’ve heard about this method but never seen it done do you have any pics?

I basically purchased a 250 ml graduated cylinder and cut that at 140ml level so that it would fit in my 5 gallon and used hot melt glue to attach it to my aquarium lid. I then ran a 1/8inch outer diameter hose from my CO2 tank to the cylinder with open end of the tube just above the water surface This is how it currently look in my tank:

I have configured the diaphragm check valves on my CO2 bottle so that if the pressure in the cylinder drops below 1 atmosphere (which occurs whenever the CO2 in the cylinder runs out) air will flow into the cylinder to prevents water from being pulled into my regulator.

A timer turns on the CO2 for only 1 minute 4 times per day. Based on the markings on the cylinder I am using 200ml of CO2 per day which (if my math is correct ) 6.6mg per hour. Could get higher levels with a diffuser. But At the time the picture was taken pearling (bubble of O2 coming off of the plant leaves) was occurring. So my O2 levels in the water were at the saturation level. So my plants cannot consume any more than that right now. So more CO2 would not in my case result in more growth.

I think the Co2 dump you mentioned is much less likely as long as you use a dual stage regulator so you can control how much Co2 goes into the reg and how much comes out.

End of tank dump is only one way you can get too much CO2 into the tank. MY problem was that bacteria started to grow in my diffuser and minerals started to build up in the diffuser stone. So periodically I had to adjust the regulator to maintain a stable flow. Additionally when the diffuser stone was wet I needed more pressure to get the CO2 to flow. But after CO2 started to flow the water got pushed out of the stone allowing CO2 flow would increase. So overall Maintaining a stable flow in my tank was hard and once it got too high and the damage was done before I recognized the problem. Also I have adual stage regulator which is very stable. So a dual stage regulators no guaranty that your flow of CO2 will stay stable. In my opinion the best setup is one that can fail and not kill your fish. The inverted bottle methode is one such system. A failure of any part of the system will not result in too much CO2.

 

[mbsqw1d]

I basically purchased a 250 ml graduated cylinder and cut that at 140ml level so that it would fit in my 5 gallon and used hot melt glue to attach it to my aquarium lid. I then ran a 1/8inch outer diameter hose from my CO2 tank to the cylinder with open end of the tube just above the water surface This is how it currently look in my tank:
View attachment 118444
I have configured the diaphragm check valves on my CO2 bottle so that if the pressure in the cylinder drops below 1 atmosphere (which occurs whenever the CO2 in the cylinder runs out) air will flow into the cylinder to prevents water from being pulled into my regulator.

A timer turns on the CO2 for only 1 minute 4 times per day. Based on the markings on the cylinder I am using 200ml of CO2 per day which (if my math is correct ) 6.6mg per hour. Could get higher levels with a diffuser. But At the time the picture was taken pearling (bubble of O2 coming off of the plant leaves) was occurring. So my O2 levels in the water were at the saturation level. So my plants cannot consume any more than that right now. So more CO2 would not in my case result in more growth.



End of tank dump is only one way you can get too much CO2 into the tank. MY problem was that bacteria started to grow in my diffuser and minerals started to build up in the diffuser stone. So periodically I had to adjust the regulator to maintain a stable flow. Additionally when the diffuser stone was wet I needed more pressure to get the CO2 to flow. But after CO2 started to flow the water got pushed out of the stone allowing CO2 flow would increase. So overall Maintaining a stable flow in my tank was hard and once it got too high and the damage was done before I recognized the problem. Also I have adual stage regulator which is very stable. So a dual stage regulators no guaranty that your flow of CO2 will stay stable. In my opinion the best setup is one that can fail and not kill your fish. The inverted bottle methode is one such system. A failure of any part of the system will not result in too much CO2.

Position of the chamber: the further down inside the tank the better right? As this will increase the amount of pressure the co2 gas bubble will be under and promote more gas exchange?

Do you have any powerhead or wave maker near the chamber to assist with circulation?

 

[StevenF]

Position of the chamber: the further down inside the tank the better right? As this will increase the amount of pressure the co2 gas bubble will be under and promote more gas exchange?

Do you have any powerhead or wave maker near the chamber to assist with circulation?

The is a filter on the other side of the tank with a spray bar at the water surface. Water leaves the spray bar horizontally. Yes the CO2 in the cylinder is at a pressure slightly higher than atmosphere.