Reference
The gear by your pool isn't as mysterious as it looks. Here's what each part does, in the order water flows through it — and why you'd care about each one.
The heart of the pool — it moves the water.
What it does. The pump pulls water from the pool, pushes it through the filter and any other equipment, and returns it clean. Nothing else works without circulation.
Why you care. Almost every piece of pool advice starts with "run the pump." Circulation is what distributes chemicals evenly, keeps the water from going stagnant, and feeds the filter. Most owners run it several hours a day; variable-speed pumps do this quietly and cheaply.
Catches the dirt and debris the eye can and can’t see.
What it does. As the pump pushes water through it, the filter traps dirt, leaves, and fine particles, returning clear water to the pool. It is periodically cleaned or backwashed to keep flowing well.
Why you care. A clean filter is half of clear water — chemistry does the rest. When pressure climbs above normal, that is the filter telling you it is time to clean or backwash it.
The in and out doors for your water.
What it does. Skimmers are the openings at the waterline that pull surface water (and floating leaves) into the system; returns are the jets that send filtered water back, aimed to circulate the whole pool.
Why you care. Empty the skimmer baskets regularly so the pump keeps strong flow. Aiming returns slightly down and around helps avoid dead spots where algae likes to start.
Doses sanitizer automatically so you do not have to.
What it does. A chlorinator feeds chlorine into the water steadily — either a tablet feeder, or a salt cell that makes chlorine from dissolved salt as water passes through it.
Why you care. It automates the most frequent chore: keeping sanitizer topped up. Salt cells need occasional cleaning of calcium scale; tablet feeders need refilling and add CYA over time, so they are worth watching.
Extends your season — and speeds up the chemistry.
What it does. Warms the water using gas, electricity (heat pump), or the sun (solar). Sits in the plumbing after the filter so only clean water passes through it.
Why you care. Beyond comfort, warmer water uses chlorine faster and grows algae faster, so a heated pool needs a touch more attention. Balanced water also protects the heater’s metal parts from corrosion and scale.
Runs the whole system on a schedule so you can forget it.
What it does. A timer (mechanical or smart automation) turns the pump and chlorinator on and off automatically, so circulation and sanitizing happen on a reliable schedule.
Why you care. Set-and-forget circulation is what keeps a pool healthy with the least effort. Smart controllers can also shift run time to off-peak hours to save on power.
