The question that you really want to ask is: Does it matter that you get foam in the tank?
I have seen plenty of negatives where air bubbles prevent fresh developer from reaching the film, leaving portions of the negative less developed than other areas. This is usually around the edges of the film where it gets stuck between the reel and two 'walls' of film.
If you rap your tank firmly on the counter top before you set the tank to rest between agitation cycles, you will not have any problems from this foaming.
The foaming is one of those things that people get puzzled about, and ask questions, without really thinking whether it matters or not. Kind of like the pink stain of some films doesn't affect printing in a way that can actually be quantified, but people still feel like there's a great need to get rid of it.
Process your film and look at the negatives. If the negatives are good - what difference does it make that the developer foams?
Nothing wrong with being curious. Nobody said anything about it being a problem.
Kodak's recommendation is for far more Photo-Flo than is needed. You only need just enough to break down the surface tension of the water. This amounts to 2-3 drops per 250 ml of solution. Much less foaming at this concentration.
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