I have a modified seaclone and the performance is actually quite good, believe it or not. I drilled a hole in the center of the top lid, then ran a rigid airline tube down the center to the bottom chamber, with a small limewood air diffuser ("red sea" type) on the end of it. That's all ... this EASY mod provides the following:
1. Stops the "cyclone" in the skimmer
2. Provides more air, without having to rely on the venturi on the pump.
I always found that the venturi never quite provided the best balance between air and flow! That was my main problem with the unmodified seaclone. I'd get the right amount of flow, but then not enough air. Get enough air, then not enough flow. This sensitive balance requires seaclone users to accept less than perfect tuning parameters, which results in mediocre performance.
Adjustment with the airstone is very easy now! I simply adjust the pump (venturi) for the flow rate I want, then crank up the air until air bubbles are just barely NOT coming out of the skimmer outlet. From that point, I adjust the air for how aggressively I want to skim. The max air setting gives tea colored wet skimmate, about a cup every day. I usually run it a bit further down, so I get darker, heavier skimmate at about a cup every 3 or 4 days.
I didn't have to do any other mod... I didn't add an extra seal, I didn't cut down the riser tube. And actually, this mod replaced the need to cut the riser tube anyway because the whole point of doing that is to reduce the "cyclone", which the rigid airtube eliminates!
I change the airstone about once a month or so, when it's performance noticeably drops.
