Tech Field Guide

Safety first

Read this before you add chemicals or touch power.

Chemicals

• Wear gloves and eye protection.
• Open one chemical at a time. Cap it when you are done.
• Store acid away from chlorine.
• Never mix chemicals in a bucket.

Add chemicals the right way

• Add chemicals to water. Never add water to chemicals.
• Keep the pump running when you add them.
• Pour slowly. Do not dump a whole bottle in one spot.
• Wait and retest. Do not stack dose after dose.
• Use the dose on the label, for this pool's gallons.

Electrical

• Treat all equipment as live.
• Do not work in standing water.
• Do not open panels, timers, or motors.
• If a GFCI or breaker trips, see the GFCI section. Do not open the panel.
• If you smell burning, or see scorch marks, leave it off and call Ron.

Target ranges

Test first. Write the numbers down. These are the R&R targets, in line with PHTA / CPO practice.

How to use this

• Fix alkalinity, then pH, then chlorine.
• High CYA makes chlorine weak. See Low chlorine that will not hold.
• Local public-pool codes may be tighter. Follow the code when it applies.

Cloudy water

Cloudy water usually means the filter is dirty, the chemistry is off, or the pump has not been running long enough.

Check first

• Test free chlorine, pH, alkalinity, and CYA (stabilizer).
• Look at filter pressure. Is it 8–10 psi over the clean starting number?
• Are the baskets full? Has the pump been running long enough?
• Was the pool just shocked, or used a lot?

Fix

• Get chlorine and pH in range first.
• Clean or backwash the filter if pressure is high. See page 13.
• Brush the walls and floor.
• Run the pump longer. Overnight if you need to.
• If chemistry is right and the filter is clean, you may use a clarifier. Use the dose on the label, for this pool's gallons. Do not add more and more.

Green or algae

Green, yellow (mustard), and black algae need different care. Brush first so you can tell them apart.

Check first

• Test free chlorine, pH, CYA, and phosphates. Chlorine is often low, or it gets used up fast.
• Brush a small spot. Green often wipes off. Mustard is a fine yellow dust, often in the shade. Black is dark dots that cling hard.
• Check filter pressure. Algae will clog the filter.

Fix

• Brush well. Vacuum heavy debris if needed (to waste if you can).
• If phosphates are high, add a phosphate remover per the label. Dual algicide usually has phosphate remover in it.
• Green: use a nylon brush. Shock per the label, for this pool's gallons. Keep the pump on. Clean the filter as pressure rises.
• Mustard: brush everywhere, including steps and behind lights. Use dual algicide per the label, for this pool's gallons. Keep brushing.
• Black: on plaster, use a wire brush to knock the cap off the black algae. Do not use a wire brush on vinyl or fiberglass. Then use granular trichlor (from the bucket), per the label, for this pool's gallons.

Foamy water

Foam is often from too much algaecide, oils, or other products — not from a need to add more chemicals.

Check first

• Was algaecide added lately? Some types foam.
• Was too much clarifier added? Or oils from lotion or a spa?
• Is calcium hardness low?
• Is this a spa, or did spa water overflow into the pool?

Fix

• Stop adding more algaecide or clarifier.
• Skim, empty the baskets, and clean the filter.
• Get calcium and other levels in range. See the ranges page.
• Foam often fades once the extra product or oils are filtered out.
• An enzyme or foam product can help only if the label fits this problem. Use the label dose for this pool's gallons. Do not keep adding it.

Low chlorine that will not hold

Too much stabilizer (CYA) makes chlorine weak. People sometimes call this “chlorine lock.” High phosphates can feed algae, which then uses up chlorine.

Check first

• Test free chlorine, combined chlorine, pH, and CYA with a kit you trust.
• How long does the pump run? Is the pool in full sun? Any algae, cloudy water, or a heavy bather load?
• On a salt pool, is the cell making chlorine? See page 14. If algae keeps coming back, a phosphate test can help.

Fix

• If you see algae, treat the algae first. See page 5.
• If combined chlorine is high, shock per the label, for this pool's gallons.
• If CYA is in range and the pool is clean, add chlorine per the label and retest later.
• If CYA is high, switch to liquid chlorine and stop using tablets. Tablets add CYA.
• If CYA is still too high (about 100 ppm or more), a partial drain and refill may be needed. Call Ron before you drain.
• Phosphates do not lock chlorine by themselves, but they can feed algae. Treat algae first. Use a phosphate remover per the label if a test is high.

High or low pH and alkalinity

Alkalinity (TA) holds pH steady. Fix alkalinity first, then pH. Use the dose on the label, for this pool's gallons.

Check first

• Test pH and alkalinity. Test calcium too if you see scale or etching.
• What sanitizer is in use? Trichlor tends to lower pH and TA. Liquid chlorine and salt systems often raise pH.

Fix

• Fix alkalinity first, then pH.
• Low alkalinity: use sodium bicarbonate (same as baking soda). It raises alkalinity with little pH change. Use the dose on the label, for this pool's gallons. Approximate rule of thumb: 1.5 lb per 10,000 gal raises TA about 10 ppm.
• Low pH and low alkalinity together: use soda ash. It raises pH and also raises alkalinity. Use the dose on the label, for this pool's gallons.
• Low pH with alkalinity already in range: use soda ash per the label, for this pool's gallons.
• High pH or high alkalinity: add acid slowly, with the pump on, in front of a return. Do not pour acid in the skimmer. Use the label dose. Wait, then retest.
• Never mix acid and chlorine.
• Make small changes. Wait and retest. Do not stack large doses.

Calcium scale and staining

Scale is hard crust, often at the waterline, on a salt cell, or in a heater. Stains can be metals or organics. Do not acid wash a pool on your own.

Check first

• Test pH, alkalinity, and calcium hardness.
• Where is it? Waterline, tile, salt cell, or heater?
• What color is a stain? Brown or red can be iron. Blue or green can be copper. Black can be a metal or an organic stain. Green can also be algae. Brush a small spot to help tell.

Fix

• Get pH and alkalinity in range first. High pH and high TA often cause scale.
• If calcium is high, do not add more calcium. Call Ron before any drain.
• Scale on a salt cell: clean the cell only as the maker's manual says. See page 14.
• For stains, use a stain-ID kit per the label if you have one.
• Do not start a drain, acid wash, or metal treatment unless Ron says to.

Low flow or pressure

High filter pressure often means a dirty filter. Low pressure and weak flow often mean a clog, a closed valve, or an air leak — not a dirty filter.

Check first

• Water level: about mid-skimmer.
• Skimmer and pump baskets. Is the pump lid tight? Is the o-ring clean and seated?
• Filter pressure vs the clean starting number.
• Are all valves in the right position?
• Air in the pump lid? That often means a suction-side air leak.
• Are the returns weak, or is only one side weak?

Fix

• Empty the baskets. Check the pump lid and o-ring. Lube the o-ring if it is dry and not cracked.
• If filter pressure is 8–10 psi over the clean starting number, clean or backwash the filter. See page 13.
• Low pressure and low flow is not a dirty filter. Look for a closed valve, a clog, or an air leak.
• If the lid is full of air: check water level, the lid o-ring, unions, and suction valves.
• If pressure is really low and you are barely moving water, check the pump impeller. Leaves or debris get caught in it. Turn the power OFF at the breaker first, then clear it with a pick or a screwdriver. The impeller is in the wet end, not the motor.

Pump will not prime or hums

A pump that will not prime is often air, water level, or a valve. A pump that hums but will not start is often electrical or a locked impeller. Do not open the motor.

Check first

• Water level. Is the pump lid tight, with a good o-ring?
• Is there water in the pump basket? Are suction and return valves open?
• Does the motor hum but not spin? Or does it run but not pull water?
• Any burning smell, heat, or a tripped breaker?

If it will not prime

• Set water to mid-skimmer.
• Turn the pump off. Fill the pump basket with water. Seat the lid and o-ring. Open the valves. Turn it on and watch for prime.
• Do not run a dry pump. If it does not prime soon, turn it off.

If it hums but will not start

• Turn the power off at the breaker or time clock.
• Do not open the motor or the wiring.
• A hum often means a locked impeller or a bad start part. This is a job for Ron.

Pump is out? Take photos

If a pump is out and may need to be replaced, take photos first. Put the photos in the Jobber notes for that visit or job. Get the pump label on the wet end — not the motor.

Photos to take

• The whole pump.
• The pump label (model and serial). It is on the wet end: the housing, the strainer pot side, or sometimes a sticker near the base.
• The motor label, as a backup only.

High filter pressure / clean the filter

Clean or backwash when pressure is 8–10 psi over the clean starting number. Write down that clean number after each cleaning.

Check first

• What kind of filter is it: sand, cartridge, or DE?
• What was the clean starting psi?
• Are the baskets already empty? Are the valves in the right place?

Fix

• If pressure is too high, the filters are dirty and need to be cleaned.
• Sand: backwash until the waste water runs clear. Then rinse, then set the valve back to Filter. Do not backwash every visit if pressure is not up. If you see sand in the pool, call Ron.
• Cartridge: do not backwash. Take the cartridges out. Hose between the pleats. If they are greasy, use a filter cleaner per the label. Do not blast the pleats with a high-pressure washer. Replace if torn.
• DE: backwash, then add fresh DE. Use the dose on the filter or the DE label. Never run a DE filter with no DE in it. If DE is coming back into the pool, shut the system off and call Ron.

Salt cell not making chlorine

A salt cell only makes chlorine when salt, flow, power, and the cell itself are in good shape. Use the salt range from the cell maker. Do not guess.

Check first

• Test free chlorine, pH, CYA, and salt. Compare salt to the cell maker's range.
• Is the cell on? Note any lights or error codes.
• Is the pump running, with good flow? Many cells need a minimum flow.
• Is the water cold? Many cells slow or stop in cold water.
• Look in the cell for white scale.
• Check the output percent or hours setting.

Fix

• If salt is low, add salt per the cell maker, for this pool's gallons. Broadcast it in the pool and circulate. Do not dump bags in the skimmer.
• If the cell has scale, clean it only as the maker's manual says (often a short, mild acid soak). Wear gloves and eye protection. Do not leave it in acid too long. Rinse well. Never mix acid and chlorine.
• Confirm flow, and that the flow switch is satisfied.
• Turn the output up only after salt, flow, and the cell are in good shape.
• If CYA is very high, the cell may be working but chlorine will still test weak. See page 7.

Heater will not fire

Safety checks only. Do not work on gas or wiring.

Check first

• Pump on, with good flow? Filter pressure OK? Valves sending water through the heater?
• Is the set point higher than the water temp? Intake and exhaust clear? Any error code or gas smell?

Fix

• Restore flow first (baskets, filter, valves). Clear leaves from intake and exhaust.
• You may use a reset only if the manual says to.
• Do not bypass safety switches, adjust gas, or open the unit.

GFCI or breaker trip

Do not open panels.

Check first

• What tripped: a GFCI, a breaker, or a time clock?
• Did it trip when a pump, light, or heater started?
• Any standing water, burn marks, or a burning smell?

Fix

• If it is dry and nothing looks burnt, try one reset. If it trips again, leave it off.

Leaks (bucket test)

Check first

• How fast is the level dropping? Any rain, splash-out, or auto-fill?
• Look for wet spots or drips at equipment.

Fix

• Turn off auto-fill. Put a marked bucket of pool water on a step and weigh it down. Wait 24 hours with no rain.
• If the pool drops more than the bucket, there is likely a leak.
• If Ron asks, compare pump off and on. Faster drop with the pump on often means equipment or pressure-side. Drop with the pump off often means the shell or suction side.