Large Tank And Co2?

[DevotedToDiscus]

I have a question which hopefully someone has had experience with and can help me out.

I currently have a planted 450l tank, and am about to upgrade to a 2,000l tank. My current tank uses pressurized CO2 with a pH controller to keep the rate stable. All my plants are super green and healthy, and I have been running this tank like this for about 3 years without issue. Given the volume of the new tank my thoughts are that I would struggle to get 30ppm of dissolved CO2 without a big volume of gas flow. The tank will be running a refugium and I plan to flip-flop the lights between tank and refugium, so that while the tank lights are on, the refugium lights are off, and vise verser. I hope that the CO2 produced by the plants in the dark refugium will help the plants in the tank, etc.

So my question is, do I need to bite the bullet and run large volume CO2 input?

Thanks

 

[TwoTankAmin]

Correct me if I am wrong, but isn't a refugium basically connected to the main tank, i.e. they share the same water? If this is the case you will not be able to have the co2 and light levels synchronized properly for the plants.

 

[DevotedToDiscus]

Correct me if I am wrong, but isn't a refugium basically connected to the main tank, i.e. they share the same water? If this is the case you will not be able to have the co2 and light levels synchronized properly for the plants.

Hi dude, the refugium is basically a sump filter inside the enclosed stand, so it will be dark in there. One segment of the refugium contains fast growing plants to absorb excess nitrates. So it will have its own lights on the planted segment, and as such I can have those lights on in the night when the plants in the tank are expelling CO2 and not absorbing nitrates, and the other way around in the day.....if you get my drift? Also the surface area of both tank and sump, might help absorbing CO2 from the atmosphere??

 

[levahe]

A 2000l planted with co2- journal please

You probably will need a large diy reactor or something similar to dissolve all that co2, and a very large bottle of co2 lol
It would be interesting to see if your plan works

 

[SO19Firearms]

It sounds far too complicated to me - too difficult to meet the co2 needs of one and the other. Algae would be a good bet.
Plus why waste all that quality nitrate on an extra tank. It would be cheaper to only dose the discus tank with nitrate and not waste it on a second.

 

[DevotedToDiscus]

A 2000l planted with co2-

journal please

You probably will need a large diy reactor or something similar to dissolve all that co2, and a very large bottle of co2 lol
It would be interesting to see if your plan works

I will do a journal, promise! The tank gets delivered on the 20th(+- a day). So will start it next week.
 
I think you are right and I will just need to run a bigger unit than I currently do. Maybe I can just get away with a bigger bottle. The stand/cabinet is about 90cm tall, so I will find the biggest bottle I can that will fit inside. Worst case is I will need to buy a second bottle and regulator so I can run them in tandem.........better raid the piggy bank again

   

 

[DevotedToDiscus]

It sounds far too complicated to me - too difficult to meet the co2 needs of one and the other. Algae would be a good bet.
Plus why waste all that quality nitrate on an extra tank. It would be cheaper to only dose the discus tank with nitrate and not waste it on a second.

Keeping the co2 level bang on is not a problem, as I have a pH regulator hooked up the co2 solenoid. My issue is how much gas it will burn through? Nothing to do with cost, as a refill is very cheap, but I don't want to have to change the bottle every week, as that will get dull. So I am guessing it means finding the biggest bottle(or bottles) that will fit in the cabinet? On my 450l I run 30ppm, which is a pH drop of 1, and that uses about 1.5kg/month. So basically a bottle change every 6 weeks...which is fine. New tank + sump will be about 5 times the water volume, so it stands to reason that I would be changing that same size bottle every week!!!! 

 . 

 

[TwoTankAmin]

DtD, you missed my point. Running co2 usually requires one to have higher levels of co2 going into the water during daylight hours and virtually none added during dark hours. However, you have a system design that always had one part of your system needing high co2 while the other part wants low co2. How will this be possible in your design, You will always need more co2 in the the water than some portion of the plants want.

 

[DevotedToDiscus]

You are right buddy. I have a co2 controller, this is an electronic measuring device of the pH reading and is connected to the valve on the co2 bottle. So, let's say the water from the tap has a pH of 7, if you add co2 at 30ppm it will drop the pH to 6(because co2 is acidic). So I set the controller at a pH of -1 from the rested tap water. This way I know I have 30ppm of dissolved co2 in my water. 30ppm is what the plants need. At night the plants release co2 so the pH drops and the valve on the bottle is closed by the controller, and during light hours the plants absorb co2 and the valve is open feeding co2. However, and here's the confusing bit, when the tank lights are on and the tank plants need co2, the refugium lights are off and the plants in there are giving co2. No matter what the plants are needing or releasing, the pH controller keeps the level of dissolved co2 correct.

This is a bit confusing, I know, but imagine this..... Tank lights on and refugium lights on, means all plants sucking up co2 and releasing O2. However, have the lights in opposite cycles means while one set of plants release co2 the others absorb it. All about photosynthesis.

Sorry if this sounds confusing buddy, is clear as mud in my head........really is
To add to that, most people run a simple system connected to the light timer. Co2 on with lights on, co2 off with lights off, then have drop checker to fiddle the bubble rate to try to get the 30ppm. With a pH controller, I don't need to worry about the bubble counter and can leave the valve wide open if I like, because the moment It gets to 30ppm the valve shuts, then as soon as it drops below 30ppm it opens. It really is that accurate.

I really need to show you to explain it clearly....... Fancy a holiday