Tank cover, good or bad for CO2?

[zozo]

There are reports of higher crop production due to elevated CO2

That is actualy something oldschool, the first reports kinda surfaced already in winter times with the use of Natural gas and Propane greenhouse heaters. They are very popular in the crop growing industry.

Since burning propane = C3H8 + 5O2 --> 3 CO2 + 4H2O
And natural gas = CH4 + 2 O2 -> CO2 + 2 H2O

Very effective, back in the day with those household Gas water heaters with pilot flame, combusting in the room it was installed. These rooms grow plants like champions. 🙂 So you realy don't need a massive burner to notice effect, for a small room a simple pilot flame is already enough to encrease production.

 

[tiger15]

I will not suggest anyone to convert his open top set up to cover top for the sake of CO2 conservation. Any gain in CO2 conservation will be offset by loss of light intensity through glass, which can be as much as 50%. For me and others who keep jumpers, having a tank cover is needed and not a choice. To compensate for reduced light intensity and distribution, I tied submersible LEDs to tank top rims.

Other winners of global warming are plankton and whales. There is likelyhood the northern pathway will open up all seasons allowing penetration of light and expansion of plankton habitat and the whales that feed on them.

 

[Oldguy]

using the tank top airspace as a reactor.

Early methods of introducing CO2 into aquariums did use a bell jar method. The area under the glass bracing strip at the rear of the tank can be converted into a linear bell jar by gluing glass ends & front so that they are below the water line and bubbling CO2 gas into this space. I considered it but went for the plastic tube with a helical insert. CO2 was bubbled up from the bottom and rose against a down current of water from a canister filter. The idea was that the gas had dissolved before it escaped through a grill at the top. Still have the kit, by Dennerle, now in storage.

 

[rebel]

Delivering O2 separately to tank water is quite easy. Just run an air stone.

Wouldn't that break your seal on the top? Also the mechanism of O2 delivery from an air stone is not from the air itself but by surface agitation. Remember O2 is less soluble than CO2.

Due to better insulation, the newer homes have worse indoor air quality than older homes due to accumulation of leaks from household chemicals.

This is not a good analogy that's relevant to this discussion.

I understand your concept though. I agree it hasn't been 'tested'. Time for you to test it.

 

[tiger15]

Wouldn't that break your seal on the top? Also the mechanism of O2 delivery from an air stone is not from the air itself but by surface agitation. Remember O2 is less soluble than CO2.


This is not a good analogy that's relevant to this discussion.

I understand your concept though. I agree it hasn't been 'tested'. Time for you to test it.

True, oxygenation occurs predominantly by breaking the surface than delivered by the air bubbles. But air bubbles, with 20% O2, is captured in the air space in contact with the breaking surface, same mechanism.

I wish I could test the concept myself, but my set up won’t allow. If I remove the tank cover, the lights that sit on top will fall in, and fish will jump out. Test is feasible and easy for set ups with over hanging lights.

 

[Oldguy]

As far as I know still in use in the UK.

 

[Sick1166]

I am running a glass cover on 60u for several weeks at a time for evaporation loss while traveling for work,
no difference on co2 results with top on so as others say keep on pumping