Dialing in Co2 recommendations.

[Sb1415]

Thanks to @Naturescapes_Rocco and @Dennis Wong for their reports on Co2 profile, I have been following my Co2 concentrations closely to see if that might be the cause of lingering algae.

Tank size - 24 gallon. In line diffuser.

This is my current schedule
Co2 on at 4am
Lights on at 8 am
Co2 off at 3 pm
Light off at 4 pm

My Hanna co2 checker
8 and 10 am - 30 ppm
3 pm - 40 ppm
5 pm - 30 ppm

Pearling starting around 11 am

I am planning to change the Co2 to come on at 2 am.

Questions

• Is it usual to need 6 hours to reach Co2 target of 40 ppm in a 24 gallon tank ? Just seems a long time
• Is there a need to stop co2 1-2 hrs prior to lights turning off ?
• How long after lights coming on does one expect pearling ?

Thanks

 

[techman81]

Or you could just bump up your bubble count a little to hit the 40ppm earlier. Just do some more testing to make sure you don't peak higher than that or wherever you want to be. 45ppm probably wouldn't hurt but keep an eye on the fish to make sure they're not bothered by it.

Also, is 8 hours of light really necessary? I don't run mine more than 7.

 

[Noahspapa]

I am going through some of the same challenges. Question - when using the Hanna test kit, at what degree of pink do you call it done. The slightest hint of pink?

 

[Naturescapes_Rocco]

That's excellent! You should be super happy with that. I think you're ple

I am going through some of the same challenges. Question - when using the Hanna test kit, at what degree of pink do you call it done. The slightest hint of pink?

Correct. Faint pink is the proper amount for any titration-- if you go until deep pink, it's too much.
The solution should turn slight pink and stay there for 20-30 seconds or more. If it's faint pink after 20 seconds, that's your number!

 

[Phish Tank]

The solution should turn slight pink and stay there for 20-30 seconds or more. If it's faint pink after 20 seconds, that's your number!

^This. The waiting 20 seconds part I missed initially, once I started doing that, it helped me read the faint pink more accurately/consistently

 

[Sb1415]

Or you could just bump up your bubble count a little to hit the 40ppm earlier. Just do some more testing to make sure you don't peak higher than that or wherever you want to be. 45ppm probably wouldn't hurt but keep an eye on the fish to make sure they're not bothered by it.

Also, is 8 hours of light really necessary? I don't run mine more than 7.

It ramps up and down over 30 min, but ended up decreasing duration anyways. This filamentous algae had been a pain.

 

[snowballs99]

I recently changed to turning on my co2 about 3 hours before the photoperiod.
Before both the light and co2 turned on the same time.

I don't think I've noticed much of a difference in pearling response.
Both need around 2-3 hours after lights on until you start seeing pearling on Rotala Wallichi.


My Rotala wallichi seemed to do infinitely better with bigger leaves after, however I also swapped to a leaner dosing instead of dosing 30ppm of nitrates all at once, I dose around 12-15ppm over the week. I think the leaner nitrates unstunted it more than the CO2.

 

[hamfist]

I'd suggest that CO2 levels in the morning are not your problem. 30 ppm should be ample, unless you have a load of really difficult plants.

Maybe running the tank just a little leaner with water column ferts will edge the algae out of the equation. Also, aim to build up plant mass, to outcompete the algae.

How long has this tank been running ? Maybe it just needs a little more time to mature and build up plant mass.

 

[JacksonL]

It’s worth keeping in mind that the Hanna CO2 test round their multiplier (50x) for simplicity. With the chemistry involved it should be 44x when testing using the smaller sample.
You may need to bump the needle valve open a small turn and see how you go. If it’s not close to reaching equilibrium after 4 hours I would look at your injection rate, surface movement (up it and turn up the CO2) or how you are dissolving/distributing the co2.

 

[Aegean]

I am using a dual needle valve and dual solenoid valve setup. One needle valve is installed immediately following one of the solenoid valves, while the other needle valve acts as a parallel bypass.

With this configuration, I’ve achieved a stable CO₂ level by adjusting the flow to 2 bubbles per second at night and 6-7 bubbles per second during the day. Since switching to this system, I have observed a noticeable improvement in plant growth, along with a reduction in both algae growth and fish stress

 

[Naturescapes_Rocco]

I've wanted to do something similar! Two solenoid/needle valves, one "high" and one "low". Have the "high" one power on for 1 hour to get the CO2 to the level I want, then it turns off and lets the "low" one keep CO2 levels stable. Will definitely do this for my next big tank.

 

[Sb1415]

I'd suggest that CO2 levels in the morning are not your problem. 30 ppm should be ample, unless you have a load of really difficult plants.

Maybe running the tank just a little leaner with water column ferts will edge the algae out of the equation. Also, aim to build up plant mass, to outcompete the algae.

How long has this tank been running ? Maybe it just needs a little more time to mature and build up plant mass.

I am using a dual needle valve and dual solenoid valve setup. One needle valve is installed immediately following one of the solenoid valves, while the other needle valve acts as a parallel bypass.

With this configuration, I’ve achieved a stable CO₂ level by adjusting the flow to 2 bubbles per second at night and 6-7 bubbles per second during the day. Since switching to this system, I have observed a noticeable improvement in plant growth, along with a reduction in both algae growth and fish stress

Interesting. Can you please post a pic of this set up, just so i can see how this is set up. I understand what @Naturescapes_Rocco meant in that we could reach stability by doing a high flow initially and a low flow to keep it stable. But i do not understand what you mean 2 bps at night and 6-7 bps at day time. Does that mean you hold the co2 at an overall stable state at say 20 ppm during night time and then during the day it would be easier to get to target range of 40-50 ppm ? I guess in one way that is a more stable level as long as one doesnt gass the fish. Thank you.

 

[BigWave]

I think some of you are getting the wrong impression. When we add CO2 it lowers the pH but this is only temperary. It is considered a false pH swing. Sure a number of people keep CO2 on 24/7 but all you are doing is wasting it. When there is no light there is no photosynthesis thus plants do not use CO2. When we talk about stability with CO2, pH and the others Its more the same consistent thing day in and day out. Kind of like when you take your prescribed medicine, same time same dosage every day.

Some links via Dennis' website.

pH swings, low pH and CO2 in planted tank

Do pH swings from CO2 injection hurt fish? Is the low pH safe for bacteria and tank cycling? Read on to find out more about the impact of CO2 injection, pH swings and low pH in a planted aquarium.

www.2hraquarist.com

kh-gh-tds /introduction-to-basic-water-parameters?srsltid=AfmBOopWEIDVXTyZPyElozJrWtYvdm68eBmrOC8VGvoDh9y8OFjiJ38X" data-host="www.2hraquarist.com" data-pending="false">

pH, KH, GH, TDS - Introduction to basic water parameters

Basic water parameters and how they affect an aquarium pH pH is a measure of how acidic or alkaline the water is. A pH reading of 7 is neutral, while numbers below 7 are acidic and numbers above 7 are alkaline. What is pH actually pH stands for "Power of hydrogen". A technical description of pH...

www.2hraquarist.com

 

[Aegean]

This is my double-solenoid and needle-valve setup., @Sb1415 @Naturescapes_Rocco

 

[Aegean]

You make a fair point—there’s no debate that plants don’t actively consume CO₂ at night.
That said, in my approach I’m also accounting for the fact that the nighttime drop in CO₂ isn’t caused only by the absence of photosynthesis, but also by gas loss through surface exchange.

With this setup, my goal isn’t to keep CO₂ high overnight, but rather to gently offset that loss in a very controlled way.
Based on my own experience, doing this has allowed me to lower the bubble rate needed during the daytime photoperiod.

For that reason, in practice I don’t see this as a major CO₂ waste. Of course, every tank is different, and this method has simply produced more consistent results in my system.

I think some of you are getting the wrong impression. When we add CO2 it lowers the pH but this is only temperary. It is considered a false pH swing. Sure a number of people keep CO2 on 24/7 but all you are doing is wasting it. When there is no light there is no photosynthesis thus plants do not use CO2. When we talk about stability with CO2, pH and the others Its more the same consistent thing day in and day out. Kind of like when you take your prescribed medicine, same time same dosage every day.

 

[Naturescapes_Rocco]

This is my double-solenoid and needle-valve setup., @Sb1415 @Naturescapes_RoccoView attachment 12811

What are the inline valves? I've not seen ones like that that were fine enough for my needs, but maybe these would work!

 

[Aegean]

What are the inline valves? I've not seen ones like that that were fine enough for my needs, but maybe these would work!

AliExpress solenoid valves and ordinary Festo-brand inline fine flow valves — if you haven’t liked this type before, you probably won’t like these either. They work for my needs at the moment.