Co2 Not Gassing Off Overnight

[Jro]

Good Morning,

The last 3 or 4 days, something strange has been happening to my tank: I have very high CO2 levels in my tank when I wake up in the morning.

I have very good surface aeration with nice rippling from the output of my FX5. I throw an airstone in at night and position it under a powerhead. I have triple checked my bubble counter and needle valve - no leaks.

I have dialed back my CO2 to almost nothing. It was at about 2 bubbles per second, now it is down to about 0.5 bubbles per second. Still, my fish are at the surface gasping within 1 - 2 hours of the lights being on. The fish are fine overnight with the airstone in.

For my CO2, I use a diffuser under the intake of my FX5.

I am at a loss at what would cause this.

Possibly Relevant Events

- I have been lightly dosing Excel (1/2 dose) to get rid of some algae. It is my understanding that Excel does not affect pH. My drop checker is consistently yellow in the morning.
- I have changed my substrate about 3 weeks ago.
- I cleaned my filter last weekend.

I am at about wits end. I end up taking a couple buckets of water out and dumping it back in to create oxygen and am having to leave my airstone in during the day.

I am just trying to understand what is happening. Any suggestions?


J

 

[burr740]

Is the regulator turning off at night?

 

[Jro]

Is the regulator turning off at night?

Yes. The solenoid is turning off the regulator at night.

J

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[burr740]

Yes. The solenoid is turning off the regulator at night.

J

k

and you are certain the co2 is no longer flowing, by looking at a bubble counter or something?

Im just trying to wrap my brain around what might be happening too

 

[Jro]

I have checked several times while the lights were off. I am confident no CO2 is entering from the pressurized system.

3 things I forgot to mention in my original post:

1.) I replaced my old diffuser with a new one on the weekend. Possibly too efficient?
2.) When this started happening, I tested for NH3, NO2, and NO3 thinking I might be getting a spike from possibly the new substrate or filter clean. Parameters were good. Maybe a false reading?
3.) I do a 50% water change every Saturday. Symptoms started happening on Monday.

Thank you for your response!


J

 

[Tim Harrison]

How are you measuring the CO2 conc in your tank?

 

[Jro]

How are you measuring the CO2 conc in your tank?

Hi TIm,

Thanks for your reply.

I have always used the drop checker as a general guideline but I mostly observe the fish. My Stiphodon ornatus (Rainbow Goby) is the most sensitive to CO2 and if I see her near the surface, I dial the CO2 down a touch.


J

 

[Tim Harrison]

Oh yes, sorry, re-read your OP you mentioned that.
This is indeed a mystery then. I can only suggest what burr already has.
The only other possibility maybe if your solenoid is on a timer. That might be faulty and somehow opening it up when you're asleep, or inadvertently timed to come on during the night?

 

[Jro]

Oh yes, sorry, re-read your OP you mentioned that.
This is indeed a mystery then. I can only suggest what burr already has.
The only other possibility maybe if your solenoid is on a timer. That might be faulty and somehow opening it up when you're asleep, or inadvertently timed to come on during the night?

Good call. I will double check the timer when I get home.

Maybe I knocked it when I was moving my filter out and cleaning it. It's one of those timers with the little tabs that you pull up or push down and I could possibly have pushed some of those tabs as it is in the same cabinet as the filter.

I will try a backup timer I have in case it is faulty.

Thank you,


J

 

[tiger15]

Good call. I will double check the timer when I get home.

Maybe I knocked it when I was moving my filter out and cleaning it. It's one of those timers with the little tabs that you pull up or push down and I could possibly have pushed some of those tabs as it is in the same cabinet as the filter.

I will try a backup timer I have in case it is faulty.

Thank you,


J

Those are bad timer. Hard to read what has been programmed, and easy to knock on additional tabs accidentally. I like the old fashion mechanical Intermatic timer that has red and green pins, easy to program and see what has been programmed. https://www.google.com/aclk?sa=L&ai...ahUKEwivl_-eoanZAhXrSt8KHcmLD1UQwg8IaQ&adurl=

 

[Tom Barr]

Drop checkers are painfully slow to respond to cO2 change.
surface scum layers and lack of water movement can prevent muchy degassign at night, plants also do not consume CO2 at night, only during the day.
Bacteria, fish and plants all respire, but at night the plants do not take it up.

If you have a surface skimmer, or good flow, some slight rippling on the surface, but not enough to break the surface in the day time, then that will help at night.
Some folks raise their outflow to ripple the water at night, then lower it with the light/CO2 gas come on.

 

[XfiXit]

What substrate did you put in the tank?
If it is a soil like amazonia it could possebly be a pH drop.

Though the Combination of changing the substrate AND cleaning the filter in the same week is pretty dangerous. Both contain a large part of your bacteria.

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[Jro]

What substrate did you put in the tank?
If it is a soil like amazonia it could possebly be a pH drop.

Though the Combination of changing the substrate AND cleaning the filter in the same week is pretty dangerous. Both contain a large part of your bacteria.

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Hi XfiXit

Thank you for your response.

I took my 3" fluorite substrate down to about 1" and just capped it with black Eco Complete. I finished about 3 weeks ago as I was doing it gradually with the fish and plants still in the tank.


J

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[Jro]

Drop checkers are painfully slow to respond to cO2 change.
surface scum layers and lack of water movement can prevent muchy degassign at night, plants also do not consume CO2 at night, only during the day.
Bacteria, fish and plants all respire, but at night the plants do not take it up.

If you have a surface skimmer, or good flow, some slight rippling on the surface, but not enough to break the surface in the day time, then that will help at night.
Some folks raise their outflow to ripple the water at night, then lower it with the light/CO2 gas come on.

Hi Tom

I adjusted my outflow to a bit more so it breaks the surface more and turned my airstone up to max overnight. It seems to have done the trick.

Thank You,

J

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[Jro]

Those are bad timer. Hard to read what has been programmed, and easy to knock on additional tabs accidentally. I like the old fashion mechanical Intermatic timer that has red and green pins, easy to program and see what has been programmed. https://www.google.com/aclk?sa=L&ai...ahUKEwivl_-eoanZAhXrSt8KHcmLD1UQwg8IaQ&adurl=

Hi tiger15,

I had a similar timer like those Intermatics many years ago. They do work very well and are really reliable.

J

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[VaughnH]

Maybe I just missed seeing it, but what is the size of your tank? If it is a 10 gallon tank, the amount of CO2 you are using could be too much, but if it is a 65 gallon tank the amount is probably too little. Unlike Tom I think a drop checker can give you a good approximation of how much CO2 is in the water. But, it only works if the water in the drop checker is distilled water with a little sodium bicarbonate in it to give you the KH you want in the drop checker. If you try to use tank water the color of the drop checker will mean nothing.

 

[ninemag]

At first this sounded like what I just went through... reg not shutting off. The solenoid wound was making noise as if it was closing, but it was stuck open. But if your not seeing anything coming into tank through diffuser it may be something else. As for the bad solenoid, I tried cleaning it, but it was toast. Cheapie aquatek/champion style solenoid. Ended up replacing it with something better


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[ninemag]

Perhaps replace with a good digital timer


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[tiger15]

Perhaps replace with a good digital timer


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I used several digital timers and returned back to mechanical. The trouble with digital timer is that programming is not intuitive, and what has been programmed is not transparrent, requiring reading the menual and pressing multiple buttons. Digital is very accurate, but it doesn’t last longer than mechanical, and can run out of battery.

 

[ninemag]

Good points- please keep us posted on this. I'm curious to know what's up


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