Co2 degas rate...

[Ady34]

Hi, we all know the co2 injection struggle....

but how can we know at what rate co2 degasses from our tanks? It will vary from tank to tank I guess based on surface area, temperature, surface agitation etc but how long before the end of a photoperiod can co2 be switched off? ......or again does that depend on photoperiod duration, intensity, plant types etc etc.
My issue is and has always been getting the co2 to a level, then maintaining it without tipping over the edge.
I think once again I will be relying upon switching the co2 on/off during 15 minute intervals a few hours into the photoperiod to keep the fish happy. I have the co2 come on three hours before lights to get it somewhere near but a few hours in I’ve noticed my siamensis gill rate increasing uncomfortably.
Currently my photoperiod is relatively short, with very low intensity in a tank full of immature slow growing plants so I guess I’m up against it. Does anybody else use the timer on their regulator to switch co2 on and off during the photoperiod to ‘level out’ co2 concentration or is this a bad idea?

Thanks or any input.

 

[Edvet]

There are different views on it. Some people say keeping it at a constant pH level can work, i personally think fluctuating CO2 levels due to the pH regulator can cause problems.
As i write this down i guess tank size might have to do with this. The faster the regulator can notice and intervene the more stable the CO2 level will be, the slower and the larger the fluctuations are, the more problems it can make, so small tanks, good flow will be faster, larger tanks with less impeccable flow will cause larger fluctuations.
I would advise to use the regulator on the "light levels CO2'' and not on the night levels CO2.

 

[Ady34]

Thanks Edvet, sorry I don’t use a ph regulator, I meant the co2 regulator to directly turn co2 injection on/off.

After 15minutes of the gas being off the fish are much happier. Incidentally it was only the siamensis that seemed affected, tetras and shrimp seemed fine, I guess some fish are more tolerant. I am going to try co2 off for 15mins back on for 30mins off for 15 back on for 30 etc etc as degas rates will likely be much faster than dissolving back in.
Maybe things will change when the plants settle, photoperiod increases and lighting intensity drives faster growth.

 

[Siege]

Hi Ady, have you seen any Dennis wong videos on YouTube? They are very good. Forgive me if you’ve seen them before.

 

[Ady34]

Thanks Siege, I hadn’t seen them but they confirm all I have been trying to achieve....but failing to
I have a skimmer, good surface agitation, a good surface area, good circulation but still don’t reach the plateaux of co2, it surpasses it. I may have to go for the less desirable slower injection rate over a longer period so during the photoperiod a level is maintained but not surpassed. I have invested in a chihiros steriliser which will hopefully increase the o2 concentration sufficiently to aid the fish.
Patience may also be key where the tank finds its level of uptake once the plants are settled and photoperiod finalised both intensity wise and duration.

 

[rebel]

On those videos, it's impressive how he has maintained flow in such heavily planted tanks, with just one filter?