JBL 6446500 ProFlora m001 Duo 2

While CO2 injection has many benefits in a planted-tank, the costs can be high which is why people mess about with DIY systems.If you are willing to get a little spendy, this dual regulator will control CO2 injection in two tanks feeding from one cylinder. I find the various CO2 canisters and connections confusing, so I hope this correct -1) The unit comes fitted with a connector that fits the standard for refillable CO2 tanks in Europe, using the DIN 477 No. 6 / BS 341 No. 8 / W21.8-14 thread. These cylinders are refillable, and JBL will sell you their m500 500g CO2 cylinder which the m002 Duo 2 attaches to. However, at least in my experience, it's not easy to get these refilled at a gas supplier unless you have an account as a publican etc. who uses CO2 for dispensing drinks. This is why sellers have come up with adaptors to match the fitting on Sodastream cylinders, which you can swap, to DIN 477 No.6.2) By using a 6mm allen key, you can unscrew the DIN 477 No. 6 fitting from the m002 Duo 2 to reveal the M10 'fine' connection that fits disposable CO2 cylinders like the JBL u500. NB in the picture I'm using a u500 and you can see the unscrewed DIN 477 No. 6 fitting resting on the left-hand gauge. The u500 is quite pricey, but cheaper 600g CO2 disposable cylinders are available at welding suppliers; I use Machine Mart. Note that the adaptor unscrews anti-clockwise and the 6mm allen key needed a tap with a hammer to loosen it off.Anyhow, with a CO2 cylinder and the m001 Duo 2 you can now go ahead and inject CO2 into two tanks at the same time with different bubble rates. I found the needle valves give a reasonable fine control of the bubbles per second. In the morning, you typically have to open the valves to let the pressure purge water in the tube into the tank. After that initial rush, you can wind down the valves and let the bubble count stabilise over a minute or two. Choice of CO2 diffusers/reactors is down to personal preference; I like the diffusers in-line with the return from the canister filter as it keeps all CO2 paraphernalia out the aquarium.Is the m001 Duo 2 worth the money? If you have two planted tanks and want to grow medium/difficult plants like buce using CO2, it probably is. You'll need to add on the costs of cylinder, bubble counters, diffusers etc. However, apart from the CO2, the other items are good value when bought from Amazon sellers direct from the Far East.