Agree with freydo on the glass diffusers haven't had much luck with them after cleaning.
Perosnally i would go with the inline, there a no bubbles floating around in your tank and its pretty cheap to make and are very efficient
As for the hagen ladders, they are some what effective, but not very efficient. A lot of the co2 will not diffuse into the water.
Also i would not place your diffuser under the intake of your canister filter, there has been a lot of dicussions on if this will damage your filter or not. I do not have any personal experience with this, but i am going off what other have mentioned about the subject.
Perosnally i would go with the inline, there a no bubbles floating around in your tank and its pretty cheap to make and are very efficient
As for the hagen ladders, they are some what effective, but not very efficient. A lot of the co2 will not diffuse into the water.
Also i would not place your diffuser under the intake of your canister filter, there has been a lot of dicussions on if this will damage your filter or not. I do not have any personal experience with this, but i am going off what other have mentioned about the subject.
