That's very interesting and I appreciate the effort (whether you have 32 posts or 1500), but I'd like to understand the science behind it. Can you explain in more detail? Maybe plantbrain can chime in if he's still active here. If I remember correctly, I've seen Tom Barr mention the benefit of sealed wet/dry filters, but maybe that's outdated advice??
CO2 and O2 are not consumed/produced at a ration of 1:1. If that were true then we wouldn’t need to concern ourselves with gassing our fish because, according to that theory, the plants would simply produce enough o2 to keep them alive. We all know this to be untrue.
Tom advocates Fick’s 1st law of diffusion as it relates to Flux. A higher level of flux is ideal for aquarium plant growth. This can be achieved by increasing flow, surface area, surface ripple, no film, and less degassing at any other part of the tank, which will lend to a higher and more stable flux. Aquariums with less of flow in general will have lower and less stable flux.
Temperature also plays a big part of gas concentration in the water. As temperatures rise, the kinetic energy increases at a molecular level. Gases form a weak bond with the water molecules at higher temperatures, which is why you generally see less dissolved gases in higher temps, this is especially true for o2. As water temperatures decrease gases become more soluble and form stronger bonds with the water molecules. This is true for all gases including co2 and o2. The trade off is most plant species do not grow as fast in cold water.
In our aquariums, because it’s similar to nature but not quite, most of the o2 comes from the air, and some comes from the plants via photosynthesis. However, the o2 that plants produce in a tank will not be fully diffused to dissolve in the water column, which is why you often see o2 bubbles rise directly from the plants to the surface. Similar to co2, o2 requires an efficient form of diffusion to be fully dissolved in water. In a high flux tank co2 and o2 are available quite uniformly throughout the tank. The high flow is also good for the distribution of macro/micro ferts to all the plants in addition to the co2 and o2. This accounts for why some folks with high co2, ferts and everything else still experience issues with algae and mediocre plant growth. Nutrient issues aside. Their temperatures may be too high, and/or they may also have poor water flow – low flux, so the plants are not thriving as they’re being told it’s a co2 issue, when in fact it’s a lack of co2 via a lack of proper flow.
BTW none of this is my own personal theory, I’m simply regurgitating someone else’s expertise to the best of my ability, but I can vouch it’s worked for me.