The pump is about halfway down the height of the tank, its aim to pump difused CO2 around the back of the plants at low level
Dave, erm bit of a story there... How does min 74ppm grab you with some seriously pis**** of fish? I'm still trying to figure this, I was at 6.4PH with 6KH - 74ppm CO2... Why? Well the test kit I was using was telling me 3KH, I also ignored the drop checker which was lime green... oooops, lesson learnt and one fatality. New test kit says 6KH which is more realistic, I'm going by the drop checker now, a PH test kit of 0.2 increments, plants that are pearling well and most importantly feedback from the fish
Have learnt a horrible lesson here, and have changed a few things to suite, have found and gone beyond the limits with almost terrible results...