From what I hear, the bubble ladder is an excellent reactor, if kept clean.
As for the CO2 production, I'd make my own, it's too easy not to. All you need is airline tubing, an empty pop bottle and a 3/8" drill bit, I think that that's the size, just a little smaller than the airline tubing. Drill a hole cleanly though the cap, cut the tubing at an angle and use a pair of needle nosed pliers to pull the tubing through, about 1/2" aughtta do. As long as you made the hole clean, the tubing will self-seal with the cap, no leaks and no goop to deal with (or buy). Plus if you somehow end up with a block in the line, instead of exploding, gas just squeezed through between the tubing and cap making a little whistle that tells you there's a block.