Rectangular pools, particularly those made of vinyl or fiberglass, are the easiest to maintain. The long, straight sides, right angles, and smoother surface make regular cleaning a breeze without having to maneuver into curves and nooks. Rectangular pools also tend to be standard sizes, so you may have an easier time when it comes time to replace liners, covers, and other parts.

The disadvantages of container pools come down to flexibility and customization. Shipping containers come in standard sizes, so the sizes and shapes are limited. They also have a very distinctive look, which may not suit the aesthetic of your backyard. 

Beyond that, while container pools are more affordable than in-ground pools, certain models can be more expensive. This includes the cost to heat your pool, since the metal walls have more heat transfer than other types of pools (which some brands circumvent with insulation).

Before deciding to install a swimming pool in your yard, there are many factors to consider. Even if you still need to figure out the specifics with your pool installer, having an idea of what you'd like will help the initial consultation. Some topics to consider include:

• Will you use salt water for your pool or traditional hose water?

• How big of a pool do you want to install? How deep?

• What special zoning laws do you need to follow for your area?

• Do you want to keep it simple or add special features like underwater lighting and waterfalls?

Both above ground and inground pools can have pool liners. Inground pools made of gunite don’t need pool liners, and you’ve probably walked along an unlined pool and felt the ripples and ridges on the floors and walls. But adding a liner over gunite or other pool types helps protect the wall panels from algae growth.