This chart might help.
You won't find anodized aluminium in there, since it doesn't apply.
Using a sacrificial anode is fine, but I would worry about the residue that it would leave in the coolant. See what Dan at dansdata.com encountered.
Given the above, I thought it might be worth looking into isolating the sacrificial anode in an area of the loop that sees no flow whatsoever, while still maintaining an "electrical" connection to the coolant. Maybe in a branch of a tee, with some kind of lint free filter?