Themuleous said:
Put the diffuser below one of the intakes of a filter, it'll diffuse into the water inside the filter, bingo!
good thinking, i don't want to put the dampeners on things, but sometimes that don't always work. I've done it in the past and if your unlucky enough to get a pocket of co2 gas inside the filter which can happen. it don't diffuse.i had a high rate of co2 from the diffuser on one occasion and had the drop checker in the blue

i tapped the filter and out came masses of bubbles....co2...non diffused. within a couple of hours we were green again. I'm not saying it does not work as it does, just be careful and check on the odd occasion
i now have mine at the opposite end of my outlet. with 1 2028 and 2 x korolia 2 on a 4 footer, co2 is/was getting to every part of the tank.
on my 60cm i have a 2028 so no need for worries there neither. diffuser opposite end to outlet....