Without going into great detail on how to plumb a pool and the technical reasons behind why I want to make this point there is one important point I'd like to make. I'll likely get into more detail in a later post. If you are having a pool put in or if you are a pool installer putting pools in you should be plumbing in two inch pipe!
There are two main reasons to do this. The first, if you ever want to upgrade features in or around your pool you have more options if the plumbing you have buried under the concrete is bigger. If you want to add a slide or a water fall, some decoratve jets perhaps, you will need to be able to get a lot more water out of your pool through those pipes. For example if you can't pull enough water out of the pool your waterfall might not get enough water and not look as good or you might not be able to build a big enough waterfall.
The second reason is that a bigger pipe can handle the same amount of water but move it slower. The effects of this are three fold. There will be less warn and tear on your equipment as it doesn't have to work as hard. The slower water flows through filtration media the better job the media can do (cleaner water). Also you can save money on your energy bill! How? You can use a smaller pump, as it's easier to move the water. It's easy to understand that a 3/4HP pump uses 1/4 less energy then a 1HP.
When your putting in a new pool the additional cost to upgrade to two inch plumbling isn't that much. The savings and future options make it more then worthwhile.