The valve should not be all the way open. Looks like you have a seaclone, which are notorious for either a) not collecting foam that well and b) being a PAIN to adjust. When I had one, I closed the valve all the way and then opened it up slowly until enough water was running through and I thought some foam would come up. That usually took like a full turn to two turns out.
You may have to fiddle with it for a few days to get it right, then it should produce some foam for you.
(also, did you make sure to clean the pump too? The impeller is very important!)
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