Pool and spa terms, without the sales voice

200 terms explained the way a technician would explain them to someone who is slightly embarrassed to ask. If a company uses a word at you and it is not here, that is worth asking about.

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200 of 200 terms

A

Acid: Lowers pH and alkalinity. Used in measured doses, not as a personality.
Acid wash: Draining the pool and taking a thin layer off the plaster with acid. It works, and a surface only has a few of them in it.
Actuator: The small motor that turns a valve when automation asks it to. When it dies, the valve underneath is usually fine.
Air blower: Pushes air into the spa jets for the bubbly effect. It moves air only, never water.
Air relief valve: The bleeder on top of the filter. Open it after service until water squirts, or the filter runs on trapped air.
Algaecide: Helper chemical. It does not replace chlorine or brushing.
Apartment pool: A pool at a multifamily property, usually with logs, posted rules and a health inspection attached. Different rules than a backyard.
AquaCal: Heat pump brand seen on a lot of North Texas pads. Slow to heat, cheap to run compared with gas.
AquaLink: Jandy automation system. It talks to Jandy valves and heaters, and to other brands with a little translation.
AquaRite: Hayward salt system. Common enough around here that replacement cells are a stocked item, not a special order.
Attached spa: A spa built into the pool that shares the same equipment. One pump, one heater, and valves deciding who gets the water.
Auto fill: A float valve that tops the pool off from the house line. Convenient, and very good at hiding a leak.
Automation: The control system running pumps, valves, heater and lights on a schedule. Excellent when it works, baffling when nobody wrote the settings down.

B

Backwash: Reversing flow through a sand or DE filter to send dirt to waste. Cartridge filters do not backwash, they come out and get cleaned.
Baseline photos: Photos taken on the first visit showing the pool and pad as found. Everything later gets compared against them.
Bather load: How many people use the pool and how hard. Twelve kids on a Saturday costs more chlorine than a quiet week does.
Biofilm: A slimy bacterial layer living inside pipes, jets and spa plumbing. It eats chlorine, and it is the reason a spa purge exists.
Biweekly: Service every other week. It saves money and it asks the pool to hold for fourteen days, which some pools flatly will not do in July.
Black algae: Dark spots rooted into plaster under a protective cap. Brushing hard enough to break that cap is most of the job.
Blow out: Pushing air through the plumbing to clear water ahead of a hard freeze or a winterization. Routine up north, occasional here.
Bond beam: The thick concrete band at the top of the shell holding everything together. Cracks here are structural, not cosmetic.
Bonding: A heavy copper wire tying all the metal around the pool to the same electrical potential. It is not a ground, and it is not optional.
Booster pump: A small dedicated pump that drives a pressure side cleaner. It only runs while the cleaner runs.
Borates: A buffer that holds pH steady and makes algae work harder for a living. Nice to have, not a rescue.
Breakpoint chlorination: Adding enough chlorine at once to burn off combined chlorine instead of feeding it. Half a dose makes the smell worse, not better.
Bromine: Alternate sanitizer, mostly used in spas. Easier on skin, more expensive, and it falls apart in sunlight.
Builder first clean: The first real service after a new build or a resurface. Startup water behaves differently and needs attention, not a routine stop.
Buyer inspection: A pool inspection during a home sale. It reports condition and age, and it is not a repair.

C

Calcium chloride: What raises calcium hardness. Adding it is easy, taking it back out means draining water.
Calcium hardness: Dissolved calcium in the water. Too low and the water starts eating plaster, too high and it leaves white crust on the tile.
Capacitor: The start component on an older motor. A pump that hums but will not spin is usually asking for this, not for a whole motor.
Cartridge filter: Pleated element filter. Nothing to backwash, but the cartridges come out and get washed by hand a few times a year.
Change order: A written change to agreed work with the new number on it. Nothing new starts without one.
Check valve: A one way valve. It keeps water from running backward into the pump or heater when the system shuts off.
Chlorine: The sanitizer doing the actual work. Everything else in the bucket is support staff.
Chlorine demand: How much chlorine your pool eats between visits. Sun, heat, swimmers and algae all raise it.
Chlorine wash: A gentler alternative to an acid wash that uses chlorine to lift organic stain off plaster. Tried first, because it removes the stain instead of the surface.
Clarifier: Makes tiny particles clump together so the filter can finally catch them. Slow and gentle, works over a few days.
Closing: Shutting a pool down for the winter. Uncommon in North Texas, where most pools run year round.
Cold plunge: A small tub run deliberately cold. Same chemistry problems as a spa and less forgiving, because the water volume is tiny.
Combined chlorine: Used up sanitizer. That strong smell at the pool is this, not too much chlorine.
Commercial route: Pools at businesses, HOAs and apartments, with schedules, logs and inspections attached. Different work, different insurance, different day.
Control board: The brain inside a heater or automation panel. Expensive, and regularly blamed for something a five dollar sensor did.
Control pack: The box on a stand alone spa holding the heater, board and relays. When a spa is dead, the answer is usually in here.
Coping: The stone or concrete cap where the deck meets the pool. It is what you grab getting out.
Copper: Metal in the water, usually from fill water, an old heater or a copper based algaecide. It turns hair and plaster green at the wrong pH.
CPO: Certified Pool Operator. A real course and a real certification, aimed mostly at public pool standards.
CYA lockout: Stabilizer so high that chlorine cannot work no matter how much you add. The only honest fix is replacing water.
Cyanuric acid: Sunscreen for chlorine, also called CYA or stabilizer. It only leaves the pool when water leaves the pool.

D

DE filter: Diatomaceous earth filter. Filters the finest of the three types, and it needs DE added back after every backwash.
DE grids: The fabric covered frames inside a DE filter that hold the powder. Torn grids blow DE straight back into the pool.
Dead spot: An area where water barely moves, so chemistry never really reaches it. Usually behind steps, under a ledge, or straight across from the returns.
Deck jet: A small arcing stream of water from the deck into the pool. Looks good, and it needs to be shut off in a freeze.
Diagnosis fee: A charge for the time spent finding out what is actually wrong. Quoted up front, and credited toward the repair when there is one.
Diverter valve: The three port valve deciding how much flow goes to the pool and how much to the spa. Handle position matters more than people think.
Dose: The measured amount of a chemical added, and written down. If nobody wrote it down, it may as well not have happened.
Drain cover: The grate over a suction outlet. It carries a stamped date and it does expire, which is a real inspection item.

E

EasyTouch: Pentair automation, the simpler sibling to IntelliCenter. Plenty of system for a pool, a spa and a couple of features.
Enzyme: Breaks down sunscreen, body oil and lotion so they stop collecting at the waterline. Useful support, not a sanitizer.
Etch: Rough, pitted plaster caused by water that went looking for calcium and found your surface. Cosmetic at first, then permanent.
Evaporation: Water leaving as vapour. An inch or two a week in a Texas July is normal and is not a leak.
Expansion joint: The gap between deck and coping that lets concrete move. Left open, it feeds water somewhere you do not want it.
Extras: Work sitting outside the weekly stop that gets quoted separately. Filter cleans, repairs and recoveries live here.
Eyeball fitting: The adjustable insert in a return jet. How it is aimed decides whether the surface circulates or just sits there.

F

Feature pump: A separate pump for a waterfall, sheer descent or deck jets. It is not part of filtration and it does not sanitize anything.
Fiberglass shell: A one piece moulded pool. Smooth and low maintenance, and very unforgiving about ever being drained.
Filter: Where dirt goes to be caught. The filter media is whichever of cartridge, DE powder or sand is doing the catching, and none of it sanitizes a thing.
Filter pressure: What the pressure gauge on the filter reads. Write down the clean number, then clean it again when the needle sits 8 to 10 psi above that, and replace the gauge when it sticks.
Flame sensor: Tells the heater the burner actually lit. A dirty one shuts everything down for safety and looks exactly like a dead heater.
Flocculant: Drops everything to the floor in a pile so you can vacuum it to waste. It makes the pool look worse before it looks better.
Flow switch: A safety that proves water is moving before the heater or salt cell fires. Low flow means no heat, and that is correct behaviour.
Flower Mound: Shop city. 2100 Riverplace Dr. ZIPs 75028 and 75022. Trucks run FM 2499 and FM 1171.
FM 1171: Cross Timbers Road. The east to west route across the top of our map, and how the western side of Flower Mound gets covered.
FM 2499: Long Prairie Road. The north to south spine most of the route runs on.
Free chlorine: The chlorine still available to sanitize. This is the number that matters on a test.
Freeze mode: The automation setting that runs the pump when air temperature drops below a set point. It is protection, so do not switch it off to save a few dollars.
Freeze protection: Keeping water moving and equipment safe when the temperature drops. Moving water is far harder to freeze than still water.
Freeze split: A cracked pump housing, filter, valve or pipe caused by water freezing inside it. It usually shows up as a leak once things thaw.
Freeze watch: The day or two before a hard freeze when the forecast is worth acting on. Much cheaper than post freeze recovery.

G

Gas heater: Burns natural gas or propane and heats fast. The right choice when you want the spa hot tonight.
GFCI: The outlet or breaker that cuts power when current strays where it should not. Repeated tripping is information, not a nuisance.
Green algae: The common one. Water goes cloudy, then green, and it gives up to chlorine and brushing faster than people expect.
Green to clean: Recovering a green pool back to swimmable. It is a multi visit job with filter cleaning built in, not one shock and a wave goodbye.
Gunite: Concrete shot through a hose to form the shell, then plastered. Shotcrete is the same idea mixed wet beforehand, and you end up with the same pool.
Gunite crack: A crack in the shell itself rather than in the plaster. Worth a real diagnosis, because some are structural and some are cosmetic.

H

Hard water: Water carrying a lot of dissolved calcium and minerals. Around here it is why tile crust and scale show up long before staining does.
Hayward: Major equipment brand. Pumps, filters, heaters, salt systems and automation, with parts that are easy to get.
Heat exchanger: The copper core inside a heater where the water picks up heat. Low pH and high chlorine eat it from the inside out.
Heat pump: Moves heat out of the air and into the water. Cheap to run, slow, and not much use on a cold night.
Heater: Adds heat to the pool or spa. Gas for speed, heat pump for running cost, and both of them hate low flow.
High limit: The safety switch that shuts a heater down when it gets too hot. It trips for a reason, and the reason is usually flow.
HOA pool: A neighbourhood association pool. Board approval, posted hours and inspection paperwork come with it.
Hot tub: A self contained spa with its own pump, heater and controls, also called a stand alone spa. Small volume means chemistry moves fast in both directions.
Hours: Monday to Friday 8:00 AM to 5:00 PM. Saturday 7:00 AM to 11:00 AM. Sunday closed.

I

Igniter: Lights the burner in a gas heater. A normal wear part, and a much cheaper fix than the control board it often gets blamed on.
Impeller: The spinning part inside the pump that actually moves the water. A pebble or a wad of hair in it kills flow with no obvious noise.
In floor cleaner: Pop up heads built into the floor that sweep debris toward the main drain. Very good when the gears and valve are maintained, expensive when they are not.
Includes: The written list of what a stop covers, agreed before the first visit. If it is not on the list, it is an extra.
Inspection week: The week a health inspector or a buyer inspector is due. Chemistry, logs and drain covers all get checked ahead of it.
IntelliCenter: Pentair automation platform. Powerful, app connected, and worth having the settings written down somewhere other than the app.
IntelliFlo: Pentair variable speed pump line. Standard on newer builds and the usual upgrade target on older pads.
Invoice match: Comparing our written scope against another invoice line by line before anybody talks price. Same work, or it is not a comparison.
Iron: Metal that stains rust brown, usually from well water or old pipe. It looks like a plaster problem and it is not.

J

Jandy: Equipment brand best known for the valves everyone recognises on sight. Also pumps, heaters and automation.

L

Langelier index: A calculation that says whether your water will scale, sit neutral, or eat surfaces. Also called the saturation index or LSI.
LED light: Colour changing pool light. The colours are selected by counting power cycles, which is why the sequence keeps getting out of step.
Licensed bonded insured: Carrying the licence, bond and insurance the work requires. Ask any company for proof of all three and expect to receive it.
Listing photo cleanup: A one time clean timed for real estate photos. Scheduled around the photographer, not around the route.
Logs: The written record of readings and service on a commercial pool. Inspectors read them, so keeping them is part of the job.

M

Main drain: The suction outlet in the deep end, and part of how the pool circulates. Modern builds use two outlets so no single one can trap anything.
Make right: Fixing our own miss at our cost. It is a policy, not a favour.
Mastic: The flexible sealant filling the expansion joint. It is a wear item and it fails quietly.
Metals: Copper, iron and manganese dissolved in the water. They stain when pH or chlorine swings, so you treat the water, not the mark.
Missed week: A scheduled stop that did not happen. It gets a makeup visit or a credit, decided the same day, not at the end of the month.
Move in recovery: Getting a pool back to normal after the house changes hands. Nobody serviced it during the sale, so it is a recovery and not a first weekly stop.
Multiport valve: The dial on a sand or DE filter with filter, backwash, rinse and waste. Never turn it while the pump is running.
Mustard algae: Yellow dust on shady walls and steps that wipes away and comes right back. It lives on floats and toys too, so those get treated.

N

NAP: Name, address and phone. Keeping it identical everywhere online is the least glamorous part of being findable.
Niche: The housing in the wall the pool light sits in. Water in the niche is normal, water inside the fixture is not.
North Texas fill water: What comes out of the hose here. Hard, alkaline, and it adds calcium every single time the pool gets topped off.

O

O ring: The rubber seal on a pump lid, filter or union. Cheap, needs the right lube, and it causes most of the air leaks we find.
OmniLogic: Hayward automation platform. The app is just the front end for a control board that still lives out on the pad.
One time clean: A single visit with a defined scope and no ongoing schedule. Good for a party, a listing, or a look before committing.
Opening: Bringing a pool back into service after time off. Around here that usually means recovering a pool that sat, not uncovering one.
ORP: A meter reading in millivolts showing how hard your sanitizer is actually working. Common on commercial pools, rare in a backyard.

P

Pad walk: Walking the equipment pad on every visit and actually looking at it. Most repairs are cheap when they get caught here.
Partial drain and refill: Draining part of the pool and refilling to dilute something chemicals cannot remove, usually CYA, salt or hardness. Boring, effective, and sometimes the only answer.
Party ready: A clean timed to an event. It is as much scheduling as it is cleaning.
Pebble: Pebble aggregate finish. Longer life than plaster, rougher underfoot, and much better at hiding a stain.
Pentair: Major equipment brand, very common on newer pads around Flower Mound and Argyle.
pH: How acidic or basic the water is. Chlorine gets lazy when it drifts high, and surfaces suffer when it drifts low.
Phosphates: Algae food from fertilizer, leaves and some fill water. Worth treating when algae keeps returning, not worth chasing on a pool that is behaving.
Photo report: Photos and the actual readings sent after each stop. It exists so you know what happened without standing there watching.
Pink slime: A pink or orange bacterial film, usually in the skimmer or behind a light. Not algae, and chlorine alone is slow to kill it.
Plaster: The classic white cement finish. Ten to fifteen years if the water stayed balanced, considerably less if it did not.
Plaster patch: A spot repair on a small area of finish. It will never colour match perfectly, and everybody should know that before it happens.
Polaris: Cleaner brand, mostly pressure side. The older 280 and 360 style units are still working all over this area.
Pollen season: Late winter into spring, when oak and cedar drop a yellow film on the water. It burns chlorine and loads the filter, and it is temporary.
Post freeze recovery: Checking the pad after a hard freeze for splits, seized pumps and cracked fittings. Do it before running anything at full speed.
Pressure side cleaner: A cleaner driven by water pushed to it, usually with a booster pump. It bags its own debris, so the filter takes less abuse.
Pump: The heart of the system, sometimes called the circulation pump. Nothing downstream of it works if it is not moving water.
Pump basket: The basket in the pump housing catching whatever the skimmer missed. Empty it before it collapses under suction.
Punch list: The list of items an inspection turned up. It gets worked in order of what actually matters, not in order of what is easiest.

Q

Quartz: Plaster with quartz aggregate mixed in. Middle ground on price, wear and texture between plaster and pebble.

R

Rate match: Pricing against a competing written quote for the same defined work. It only works when both scopes are on paper.
Raypak: Gas heater brand found on a lot of local pads. Serviceable, and parts are usually available.
Resurfacing: Replacing the interior finish. A big job, and the right moment to deal with tile, lights and fittings while it is empty.
Return jet: Where clean water comes back into the pool. Aim matters, because dead spots get created right here.
Robot cleaner: A plug in cleaner with its own motor and filter bag. It works independently of the pool pump, which is the whole point of it.

S

Salt: Dissolved salt is the raw material a chlorinator turns into chlorine. It does not evaporate, so you only add it after water leaves.
Salt cell: Salt chlorinator blade. White crust means dirty. No chlorine with a clean cell means dead.
Salt error codes: The lights or codes on a salt system for low salt, low flow, cold water or check cell. They point at a cause, they do not diagnose one.
Salt system: The box and cell that make chlorine from dissolved salt. It still needs balanced water and a sane stabilizer reading to work.
Saltwater pool: Still a chlorine pool. The cell makes the chlorine on site instead of you hauling it home in a jug.
Sand filter: Filters through a bed of sand. Forgiving, cheap to run, and the sand gets replaced every several years.
Scale: Hard white or grey calcium deposit that came out of solution. It feels like sandpaper on tile and steps.
Sequestrant: Holds metals in solution so they cannot stain. It wears off, which is why it goes on a schedule.
Shaft seal: The seal between the wet end and the motor. When it fails, water drips onto the motor, and that is how motors die.
Sheer descent: A wide flat sheet of water falling into the pool. Beautiful, and it evaporates water faster than you would guess.
Shock: A large dose of chlorine to clear water and burn off combined chlorine. It is a verb, a noun, and not a weekly ritual.
Single speed pump: Old style pump, one speed, on or off. Simple, loud, and the most expensive thing on the pad to run.
Skimmer: The mouth in the wall pulling surface water and floating debris in. Most of what a pool collects arrives here.
Skimmer basket: The basket inside the skimmer. A full one starves the pump, which is a much bigger problem than the leaves ever were.
Skimmer weir: The floating flap in the skimmer throat. It holds debris in when the pump stops, and it goes missing constantly.
Skipped week: A week deliberately not serviced, agreed in advance. Different from a missed week, and it comes off the invoice.
Soda ash: Raises pH quickly with a small push on alkalinity. Very easy to overdo.
Sodium bicarbonate: Baking soda. Raises alkalinity with only a small push on pH.
Spa drain and refill: Emptying a spa and starting over on fresh water. Every three to four months on normal use, sooner after a crowd.
Spa jets: The nozzles pushing water and air at you. They unscrew and clean, and a dead jet is usually just a blocked one.
Spillover: Running the spa so it overflows into the pool. It keeps the spa water moving and treated along with the pool.
Sta-Rite: Pump and heater brand, now part of the Pentair family. Plenty of older Sta-Rite pumps are still running fine.
Storm debris: What a North Texas storm puts in your pool in about twenty minutes. Big pieces out first, chemistry second.
Suction side cleaner: A cleaner that runs off the suction line and sends everything it picks up into the pump basket and filter. Cheap to buy, harder on the filter.
Summer demand: The stretch when heat, sun and swimmers eat chlorine faster than any other time of year. Same pool, different appetite.
Swim spa: A long spa with a current to swim against. Part exercise equipment, part spa, and the chemistry follows spa rules.

T

Tanning ledge: The shallow shelf for chairs and small kids, sold by some builders as a sun shelf. Warm, sunny and still, which is why algae finds it first.
Tannins: Brown, tea coloured water from leaves and organic debris sitting too long. It looks like a stain problem and it is a chlorine problem.
TDS: Total dissolved solids. Everything in the water that is not water, and it only comes down with a drain and refill.
Test kit: Reagent based testing with drops and comparators. Slower than strips and considerably more accurate.
Test strips: Dip strips for a quick read. Fine for a rough check between visits, not for deciding a dose.
Tile calcium: The white crust on waterline tile from hard water and evaporation. It comes off with a bead blast, not with a scrub brush and hope.
Timer: The mechanical or digital clock running the pump. Total run hours matter more than the exact hour of day, within reason.
Topside panel: The control pad on the spa rim. When the buttons stop responding it is often the panel and not the pack.
Total alkalinity: How well the water resists pH swings, often shortened to alkalinity. Set this first and pH stops fighting you every week.
Total chlorine: Free chlorine plus combined chlorine. Subtract free from total and the difference is what is nagging you.
Transformer: Steps voltage down for low voltage lights. It lives near the pad, and it is often what actually failed instead of the light.
Trip fee: A charge for driving out. It covers the truck and the hour, and it gets stated before the trip, not after.
Turnover rate: How long the pump takes to push the whole pool through the filter once. One full turnover a day is the usual target.
Two speed pump: High for cleaning, low for filtering. A middle step between old and new, and no longer the value pick.
Two step job: Work that honestly needs two visits, like a filter clean after a heavy chemical treatment. Said out loud in advance instead of discovered later.

U

Union: The threaded coupling letting equipment come apart without cutting pipe. Hand tight plus a nudge, no wrench heroics.

V

Vacuum as needed: Vacuum when the floor needs it, not because it is Friday.
Valve: The handle that decides where water goes. Most service calls that feel mysterious start with a valve somebody turned.
Variable speed pump: Adjustable speed pump. Running longer and slower filters better and costs less than short bursts at full speed.
VGBA: The federal law setting suction outlet safety rules, including rated and dated drain covers. It is why your cover has an expiry stamped on it.
Vinyl liner: A fitted vinyl sheet over a frame wall. Cheaper up front, replaced every so often, and a wire brush ends it.

W

Waterline tile: The band of tile at the water surface. It is there because that line is exactly where scale and body oil collect.
Weekly service: Full service every week: skim, brush the walls and steps, vacuum as needed, baskets, test, dose, check the water level and walk the pad. Not a net and a wave.
Winterization: Draining and protecting equipment so a freeze cannot damage it. Full winterization is rare here, targeted freeze protection is the norm.
Written yes: Approval in writing, with a dollar amount, before extra work starts. A verbal maybe in the driveway is not one.

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