CO2 not off gassing overnight?

[ForestDave]

Hi.
A week ago I changed my filter output from a full width spray bar to a rotational flow. I had some big rocks in the middle of the tank which stopped the CO2 getting to the plants at the back. Either way I’d obviously been doing it all wrong as now the drop checker easily reads a lime green everywhere. The problem is that, although my cheap ph pen shows a 1ph drop from the water change reading the drop checker is too lime green/yellow I think and it stays that way overnight. The ph stays about 0.5 ph lower than the original ph and I’m worried this is bad for the shrimp as I’ve lost about 6 in the last week. I have a lidded Roma 200 but even opening the lid didn’t change anything last night. Should I ignor the ph pen and just go by drop checker and maybe put a decent air pump/stone in to off gas the CO2 after the lightning period or am I worrying over nothing?
Set up is Fluval FX6 and diy reactor. With a Newa powerhead aiding the flow. Ph is 7.45 before using CO2
Apologies for the stream of consciousness but any help would be amazing.
Thanks!!

 

[Garuf]

Co2 often doesn’t fully off gas and the drop checker will be giving a lag in what is really in the water.
What I have noticed lately is that since changing to permanently running surface skimmers, co2 use has gone up, but also that the tank is off gassing what’s injected much faster and I now do get a blue dc by the morning. I also assume I have a more stable o2 level because of high o2 boundary layer water is being pushed into the bottom of the tank by the skimmer.

 

[Wookii]

Hi.
A week ago I changed my filter output from a full width spray bar to a rotational flow. I had some big rocks in the middle of the tank which stopped the CO2 getting to the plants at the back. Either way I’d obviously been doing it all wrong as now the drop checker easily reads a lime green everywhere. The problem is that, although my cheap ph pen shows a 1ph drop from the water change reading the drop checker is too lime green/yellow I think and it stays that way overnight. The ph stays about 0.5 ph lower than the original ph and I’m worried this is bad for the shrimp as I’ve lost about 6 in the last week. I have a lidded Roma 200 but even opening the lid didn’t change anything last night. Should I ignor the ph pen and just go by drop checker and maybe put a decent air pump/stone in to off gas the CO2 after the lightning period or am I worrying over nothing?
Set up is Fluval FX6 and diy reactor. With a Newa powerhead aiding the flow. Ph is 7.45 before using CO2
Apologies for the stream of consciousness but any help would be amazing.
Thanks!!

If you are getting a lighter drop checker than before, it would suggest your are getting greater dissolution of the CO2, and/or less off gasing. Has the level of surface agitation reduced as well? Remember your baseline pH reading should be with a glass of tank water left to stand and fully off-gas for 24 hours - is that the case with your 7.45pH reading?

For what its worth, my tanks never fully off gases the CO2, even with decent surface agitation - the green just gets a little lighter during the photo period.

I would drop your injection rate back a bit until you get your preferred drop checker colour in the first instance.

 

[Zeus.]

Does it matter if the tank doesn't fully degas ? I'm with @wooki on this - no it doesn't - as long as there's enough O2 in the tank. One of my tanks does degas the other doesn't. If the tank does fully degas it is a great indication of good gaseous exchange. One tank has DC blue in morning and other is still green when CO2 comes back on 🤷‍♂️

Trust your DC (Drop Checker) colour change. Even if the pH pen isn't great it is still handy as it will be good enough to see if the pH is stable, the reading on the pH pen is irrelevant as long as it remains the same from lights on till CO2 off. I havent calibrated my pH pens in a long time and I have the buffers to do it, I am not interested in the actual pH it the change in pH from lights on.

If the pH remains stable ( I use a 0.1pH change as stable) and the DC goes light green soon time later whilst pH is stable -job done

 

[ForestDave]

Thanks guys!
That’s all great info.
Yes I’m not getting the surface agitation I was with the spray bar and the CO2 dissolution is massively improved. So two reasons for the dc not changing much. I can see why I’ve been struggling with some plants now, my previous setup was worse than I thought. I don’t think I was jetting the water out of the spray bar at a high enough pressure. Either way I stuck some flake in the tank yesterday and it looked like a snow globe with the flake clearly spread from top to bottom going around in a circle with the rocks sat in the middle. I now need to work out a good plant for the rear of the tank that isn’t going to lean over with the flow. I was thinking of a tall bushy crypt?
Thanks again
Dave

 

[si walker]

Picking up this thread again while I'm on the train.
I watched a great YouTube shop tour that was in a Japanese Aquarium Store. It was in the evening and the tanks we off gassing with what looks like an open ended airline gently bubbling away.
I thought, hell I forgot about that.
It was simple to set up as I already had a small air pump, plus gave me a really good reason to tinker about. Again.
I set it on lights off for 5 hours but the DC shows little or no colour change.
I like having it there actually.

But isn't this an important part of getting happy plants and life in the glass box?
Or am I barking up the wrong tree?

I may try a very small air stone if I can find one?
Some people were using a bamboo chopsticks at on point!

Let me know your thoughts.
Have a decent day.

 

[Wookii]

Picking up this thread again while I'm on the train.
I watched a great YouTube shop tour that was in a Japanese Aquarium Store. It was in the evening and the tanks we off gassing with what looks like an open ended airline gently bubbling away.
I thought, hell I forgot about that.
It was simple to set up as I already had a small air pump, plus gave me a really good reason to tinker about. Again.
I set it on lights off for 5 hours but the DC shows little or no colour change.
I like having it there actually.

But isn't this an important part of getting happy plants and life in the glass box?
Or am I barking up the wrong tree?

I may try a very small air stone if I can find one?
Some people were using a bamboo chopsticks at on point!

Let me know your thoughts.
Have a decent day.

I still see no point in attempting to off-gas CO2 at the end of the photo period. All CO2 injected tanks should have decent surface agitation anyway, and that alone will off-gas more CO2 from photo period levels, than plants might release during the night. You'll rarely be able to off-gas all the CO2 out of the water column (in fact it's difficult to off-gas much at all of it unless you're running a short phot period).

If the aim of adding an airstone is also to increase DO levels during the night, I also think it's misguided. In a heavily planted tank you will likely be fully DO saturated part way into the photo period, so the addition of an airstone will simply off-gas the DO back down to equilibrium levels, which is surely counter productive.