Yeh I'm certain circulation is still key, and probably more so with the passive method. It could be completely pointless on a tank my size, possibly better suited to 20G and under.. we'll see!Ah, I can see the rudimentary purpose and how it works.
Quite simple really, but sometimes the simple stuff works the best!
Though the upside down cup, I fail to see how this will distribute the Co2 throughout the water column, am used to atomisers / diffusers (though they tend to get blocked every now and again which gets annoying sometimes) so am wondering if putting a small power head or something near a Co2 distributer of sorts will help move the Co2 around the tank this getting to most if not all the plants.
Just a theory anyway, I like the eBay link you gave for the line and reg, at £14 you can’t go wrong really so it’s def worth a try.
Will keep having a look and see if can come up with something that’s more suited for me but that’s fantastic information, good as gold!
The chamber would need to be pushed as close down to the substrate as possible, around 6 inches above, as this makes the trapped co2 more pressurised, and therefore forces the diffusion. It'll be easier for gas exchange to happen between the bubble of gas in the chamber than it is at the water surface due to the difference in pressure - i think is the idea anyway.
My birthday coming up so maybe I'll do injection properly and convert a co2 fire extinguisher