Thanks for bumping this thread up. I must admit I'm amazed I didn't think of this myself since I use this stuff all the time at work. Some of you know I'm a hyperbarics research technician at UB and we're all about sodalime for all sorts of closed-circuit breathing systems, hopefully I can offer some practical insight. First off Gary, you're right, this stuff cannot be re-generated. We go through hundreds of 5g buckets of it per year, if there was a way to economically re-charge it, we would have found it
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Second, be careful with it. It is pretty basic, especially when mixed with water and you should really use gloves when working with it.
Lastly, getting full use out of it. We use MUCH higher loads on it in closed circuit rebreathing systems. For general reference, we burn through around 2 liters or quarts of it in a few hours worth of experimentation and I can confirm that at high flowrates, canister design makes a big difference but for lower flows, it's not that big a deal. And I'm talking phyisological flows, WAY higher than anything we'd use on an aquarium even at their slowest. So if I were designing a container for a reef application, a simple 2L bottle with pinholes in the top and airline glued in the bottom should be fine. I would not however be keen on using one of those canister filters for DI units as they offer no real in-line use of the media. They're desinged well for fluid applications, but probably not great for air applications like these.
Lastly FWIW, tests like Tom has done here show how slow the rate of communication our tanks have with the atmosphere in our homes is. It also proves how important air injection really is to seawater systems and how much we can actually "do" to change gas concentrations in our water with a skimmer. Great work Tom, and if I ever get serious about water chemistry and find myself with a CO2 problem in the winter, I may just do this
