Shade For Green Water In Outdoor Pond? Options

[Forever-mango]

I currently have a 1000ltr pond with about 50cm tall of water in it. It was green water (all water from rain) with some aquatic plants floating. Today I decided to do a total water change approx 700ltrs, and seeded it with about 20 ltrs of old green water.

I would like to ask:
1. I have 60% shade cloth over the pond, is that a good thing?

2. Is it a must to have air pump in the water? Or can I leave to have no aeration in the water?

3. Do I need filtration? If not how often to I change the water and how much?

Regards
Mango