Fixing pond issues naturally

I had a good pond ecosystem going on last summer, with water filtering plants, oxygenating plants and fish, when the heat and drought struck.
Grass dried up, and my three little sheep walked into the pond to drink, every day a little deeper...piercing the pond lining with their hooves.
I first didn't realise this was happening (my focus was with the renovation of our house), and by the time it dawned on me, I had to do a emergency pond rescue; moving the plants and the fish into buckets and tanks, pump out the water, replace the pond lining...

After the pond renovation the biological balance of the pond was off, but I was hoping it would recover by itself the next season.
I built edges around the pond that keep the sheep away, and am making sure they have drinking water elsewhere.
This season has been even hotter and drier. The pond water is green. The water filtering plants and the fish have all survived, but the oxygenating plants didn't survive the winter. Whenever I'm topping up the pond I make sure the water is falling in, bringing some oxygen with it.

I'm aware there are chemicals that would clear up the green water, but I want to keep my pond natural and be gentle with the plants and the fish.
I found out there's a French company (they also ship abroad) with 100% natural solutions to any and all pond problems. I ordered some water fleas that I think will multiply as they're consuming the micro algae, rendering the water clear, and new oxygenating plants that also use the excess nitrates as they grow.

I know this sounds like "blatant advertising", but 1) I'm not getting any compensation from them for my praise and 2) I'm genuinely happy and enthusiastic about finding them, which is why I want to let others know this interesting source of biological pond ecology boosters.

Their website is very clear and resourceful, prices not too elevated, service is good and fast and most and foremost, the received plants and water fleas were very healthy, thanks to the good (origins and) packaging.

You can take a look your self, they're called Aquazolla .

I would suggest adding an aerator as that seems to be the solution I have read.