By Fran J. Donegan
When compared to an in-ground pool, a large above-ground pool is considerably less expensive—plus it goes up in a fraction of the time it takes to install an in-ground pool. But one thing the two have in common is the need to keep the water clean with various pool equipment. Many people don’t realize that when they buy a large above-ground pool, a filtration system has to be part of the package. Without it, those thousands of gallons of water in a typical pool will become unpleasant and unsanitary.
The Basic System
A filtration system consists of a skimmer, a pump and a filter.
Pool equipment manufacturers size skimmers to match the size of the pool, and they are usually part of the pool package. The skimmer is usually attached to the side of the pool, where it collects pool water that flows to the pump and filter.
Besides being the entry point for the filtration system, the skimmer can remove large items that fall in the pool, such as leaves and grass clippings. Skimmers often have a collection basket that needs to be cleaned periodically. The level of the water in the pool should never fall below the level of the skimmer. If it does, the pump will be sucking air rather than water and could burn out.
The current trend is to package a compatible pump and filter with the pool. That system usually works fine, but there may be times when the pump needs to be replaced because it malfunctions or it doesn’t work for your circumstances. Above-ground pool pumps range from 0.75 horsepower (hp) to 1.5 hp. The rule of thumb is that any pool that holds 12,000 gallons of water or more needs a 1.5-hp pump; smaller pools can use a 1-hp pump. You can find the number of gallons a pool holds in the manufacturer’s literature, but, in general, 12,000 gallons corresponds to a 24-foot-diameter round pool or a 16- by 32-foot oval. It is important to get a pump designed for above-ground pools because they are usually placed below the pool’s waterline. Pumps for in-ground pools are placed above the waterline.
- Pump Speed
Most above-ground pumps run full speed all the time, but two-speed models are more energy efficient. The lower speed is fine for routine filtration, and the higher speed can be used when many people are in the pool together or when a pool vacuum is hooked up to the filtration system.
The filter should be matched to the pump. Most manufacturers make filters for both above-ground and in-ground pools, with the above-ground filters being the smaller models. The filters listed below are ranked from least expensive to most expensive.
- Sand Filters
This is the most common type for above-ground pools. They are filled with a special grade of sand that can remove particles down to about 20 to 30 microns. A micron is short for micrometer or millionth of a meter; there are 25,400 microns in an inch. Sand filters need to be backwashed, which is a process of running water backwards through the system to flush out impurities.
- Cartridge Filters
These filters are becoming more and more popular for above-ground pools. They can filter down to five to 20 microns. To maintain them, remove the filter and hose it down.
- Diatomaceous Earth
Also known as DE filters, the filtering medium consists of the fossilized remains of diatoms, hard-shell algae. These remove material down to three to five microns. As with sand filters, DE filters need to be backwashed periodically.
When the operating pressure of the unit rises about 10 pounds per square inch (psi) over normal operating pressure, which is usually seven to 12 psi, it is time to backwash or clean the filter. Rising pressure means dirt is clogging the filter. If it drops, there is an obstruction in the line somewhere.
The filtration system is one part of the water cleaning process. Chemicals and other additives sanitize the water.
Other Pool Equipment
A filtration system is a must, but there are some other accessories that can make the pool experience more enjoyable.
Pool heaters are becoming increasingly popular for above-ground pools because they extend the pool season. The types of heaters include natural gas and propane, heat pump heaters and solar heaters. Heat pump heaters use the heat in the surrounding air to help heat the water. Solar heaters use the heat from the sun. While gas and heat pump heaters are usually placed next to the pool for convenience, solar collectors are often installed a distance away from the pool, sometimes on the roof of the house or garage. Keep in mind that the pump you select has to be able to move the water through the entire system.
A pool dealer can help determine which size heater is best for you. The size depends on the capacity of the pool, the surface area and how quickly you want the temperature of the water to rise. Pool equipment manufacturers have charts that simplify the selection process.
As mentioned, water enters the system through the skimmer. From there, the water will flow through the pump, filter, heater and any other accessories, then return to the pool. Most systems rely on flexible tubing that is attached to the equipment with hose clamps.
Pool equipment should be placed on a level surface, such as a few patio pavers dug into the ground. You will also need electrical service to run the pump. Electrical codes require a GFCI receptacle at outdoor locations.
An above-ground pool is a great addition to any yard. To get the most value from your investment, choose the equipment that matches the pool and your needs.
DIY expert Fran Donegan writes for The Home Depot about home improvement topics. He provides useful info ranging from installing an above-ground pool to building an outdoor patio. Fran is also the author of several home improvement books, including Pools and Spas.