Population Loyalty

The quickest ane easiest method is to station Troops on that planet. Troops will quell riots and pacify planets allowing you to build other facilities such as an Urban Pacification facility.

You can also, along with the troops, have warships in orbit around the planet. That'll make them happier too.

In my very limited experience, I've found that 10-50 troops (probably overkill) helps conquered population get in harness and pulling for my side rapidly. I play it cautious and leave them there afterwards as defense and to keep the pop focused.

Figure 50ish for homeworlds and other big pop planets, and 10 for minor colonies.

Works for me too. Troops work faster and better.

I sent troops about 100 of them i know was overkill down there but the population was wiped out they did have 1 troop defending and 2 facilities that my troops destroyed i wanted to capture the population not cause a genecide for their species how do not kill them?

I don't think troops kill regular population ..I think they only target other troops and militia. Its more likely it was your other warships that killed the population from orbital bombardment. Plus, the facilities are killed the same way, via orbiting warships not troops.

You can have your ships not kill the population or facilities by adjusting the strategies for the fleet or that type of ship (or both).

Think of friendly troops as a para-military force to help keep the populace loyal and "happy". Kind of like KGB battalions.

You'll want more than 20 troops. Try at least 100. I've put about 10 on minor worlds and 100 on major ones. If the pop is really high you can always increase it a little. Once you reach a certain point (I don't know the formula yet) they'll stay happy. You should also have less of a problem after destroying their empire and they become assimilated.