off hand ive not seen a true external diffuser, only diy ones people have made that are inline, which are just like the one that comes with the more expensive kit (the one you have) which of course you should be able to fit externaly since its supply of water is from the filter only right? if your worried about it being an eyesore fit it closer to your filter and hide it within your cabinet
Would love to my friend but it is not an external one. It fits together like a toy snake and it has a hole in the back of it which I can only image that it is for build up of water pressure, so water does leak from it. I know that my Bamboo Shrimp likes it as he was around there tonight filtering the water for me, not looking forward to the bill when he sends it to me
If I could get one that has an in and out at both ends like my external heater then I would be very happy and I think that it would be even more efficient as the CO2 would be in the water composition even more before it comes out at the other end.
Martin