I just took a gamble on a Seaclone 100...Got it for $10.00 new...
I put it ON the 10 gal sump on my 20 gal Nano reef...
I read the instructions, twiddled with it ...read the instructions, twiddled with it some more and then read the instructions again and said OH, I GET IT...
...
Open the air valve all the way (take it out) You should see large air gaps in the "J" tube ...TOO much air not enough water.
Then close it all the way <bottom out> you should see solid water
clear in the "J" tube...TOO much water not enough air.
Then open it back up between 3/4 and 1-1/2 turns until you see solid foamy water in the "J" tube (no air gaps) Just Right. Mines about 1-3/4 turn.
The leave it run for a day or two to "break in" and depending on your Bioload it "Should" produce a good quantity of sticky dry foam that spills into the collection cup...
Slight adjustments from there and mine seems to work fine.
Watch the "MIX" in the "J" tube, as foamy as possiable without air gaps, and it should start to produce for you.