Suggestion: Immigration Routes?

You can do that manually, with transports. I keep a transport on hand in each star cluster to handle movement of populations from overcrowded planets over to high-quality/high-morale planets.

You can only move 1 billion at a time, but usually this is sufficient, and transports are free (no maintenance).

I gotta do that more often...I never relocate my population...just never thought of it.

Does it make a noticable difference?

Alzandrion --

It can, if you're having morale problems e.g. you just got a heavily populated world by culture conquest, but the AI destroyed *all* its improvements first. Remove some of the overcroweded folks and drop 'em on a PQ 31 paradise world.

It makes a difference because if you colonize a PQ 18 planet and a PQ 25 planet at the same time and you run them both at 100% morale for maximum growth, eventually the PQ 18 planet won't be able to sustain that rate of growth. At some point both planets will hit the population growth cap and they will begin growing at the same rate, (typically this happens around 2.5 billion population). When that happens, the PQ 18 planet's morale will drop much more quickly than the PQ 25 each turn, and in order to keep their morale high you'll have to drastically lower your tax rate, thereby hurting your overall economic situation.

In order to fix this, you build a transport and park it on the PQ 18 planet. Since both planets are growing at the same rate but unequal PQ, you'll have to constantly transport population from the PQ 18 over to the PQ 25 planet as long as both planets continue to grow. (And yes you do want all your planets growing all the time.)

There's another wrinkle: The two planets can be orbiting the same star. Suppose you have a PQ 18 and PQ 40 planet orbiting the same star. You want to put population on the PQ 40 planet, but not the PQ 18 planet. Unfortunately, transports cannot be landed on a specific planet; the population is evenly(?) distributed among planets in the system.

The solution is to build a colony ship in the system, put most of the population on it, and land it back on the PQ 40 planet! This is an undocumented feature: you can land a colony ship on an already-colonized planet. (The colony ship icon doesn't appear, but you can still click on the planet to land the colony ship.) This destroys the colony ship, but colony ships have a much larger (unlimited?) max population capacity. This way, you avoid morale problems on the PQ 18 planet.