I have been using Hocut 795 it is a bit pricey but I do not have foaming problems any more.
NEWER DOOSAN 30 X 16 WITH THRU SPINDLE COOLANT (HANGSTEFERS)
HAVING FOAMING PROBLEMS AND PUMP IS SUCKING FOAM,,, COOLANT IS FULL BUT THE THRU SPINDLE PUMP SOMETIMES MOANS WHILE SUCKING FOAM.
I AM USING ANTI FOAM BUT DOES NOT WORK,, ANY GOOD COOLANTS OUT THERE?
BAD DOG
I have been using Hocut 795 it is a bit pricey but I do not have foaming problems any more.
The Hangsteffers with anti foam additive never has given me problems.
My guess is you are sucking air somewhere.
If youare using S500cf with the anti foam additives, (I was) and having foam issues, you might try Hangsterfers Neocut 300. I have a couple of 1000psi pumps and have no foam issues....