If you use a native floating or emergent type plants around about 1/2 the pond, 1/3 etc, then harvest the floaters 2-3x a season, to maintain 30-50% coverage, you'll not have algae issues.
Also, the algae is a temporary season thing, generally April till about Sept/Oct.
As far as algae under the surface, sodium percarbonate works VERY effectively.
It'll kill algae on plants and surfaces, you spread it out, it's basically dry peroxide salt. It'll float down and kill the algae, but does not harm plants or livestock.
You can get larger quantities (eg 50 lbs bags etc). About every 1-2 months, hit the hot spots.
These are the two main things I would suggest.