Foaming power steering fluid

[xavier]

I have a slight leak in my power rack , so every few weeks I top up the fluid. This will have to do until I have some time to fit a new rack. I took the cap off of the resivior the other day shortly after driving the car and the fluid seemed bubbly and foamy. Is this normal?

[e30topless]

if you have a leak it will be sucking up air during operation, this causes the foaming of the fluid,