16.2 Problems and Solutions: Cloudy Water, Algae, Equipment Faults

16.2 Problems and Solutions: Cloudy Water, Algae, Equipment Faults

Quick Answer: Most water problems are filtration or circulation problems wearing a chemistry costume. For cloudy water, prove flow, media, and air before you dump chlorine; then check CSI/scale, high pH, and organics. Alum and clarifiers help particles reach the filter; they are not a pump. Phosphates feed algae; they are not a magic clarity number. Algae (green, mustard/yellow, black as types) wants brushing + residual + shock + filter work, not copper as the first product. Eye-burn chlorine complaints are often combined chlorine with low free chlorine, not a tank that is too strong. Equipment faults—no flow, high pressure, heater not firing, feeder not pumping—use Chapter 7 and Chapter 8 gauges and interlocks. Adding more chlorine is often the wrong first move when the filter is air-bound.

Domain 5C on the 2025 AFO outline includes facility maintenance as more than painting the deck. Operators get paid to diagnose. Chapter 4 taught oxidation. Chapter 5 taught saturation. Chapter 7 taught pumps, filters, heaters, and feeders. Chapter 8 taught pressure-up / flow-down as a mechanical sentence. This section is the Tuesday-morning version: a cloud, a green wall, a smell complaint, or a silent heater, and a line of swimmers at the gate. Independent OpenExamPrep teaching uses those public chemistry and mechanical facts plus ordinary commercial troubleshooting. It is not a second copy of the pump-curve lecture and not a reprint of Chapter 7 loading-rate tables.

Cloudy water: prove the filter is actually filtering

Close if you cannot see the drain. Clarity is a safety rule, not a cosmetic one. Then ask, in this order: is water moving through media?

Flow. Read the flow meter against the design turnover you calculated in Chapter 8. Feel the returns. Look at the hair-and-lint strainer: a dry basket on a flooded-suction pump is one story; a basket packed with debris is another; a closed suction or return valve is a third. If the pump is cavitating or the strainer lid is hissing, you do not have a chlorine problem yet. You have a hydraulics problem.

Media. Sand that is old, diatomaceous earth (DE) that has dropped off the grids, or cartridges that have collapsed will pass turbidity. Chapter 7 taught differentials: influent pressure up, flow down usually means the tank is loaded or the downstream path is throttled. Backwash or clean before you invent a new chemical program. Opening-week silt from Section 16.1 loads media fast. A log that says shocked it twice with a filter that has not been cleaned is a closed loop of wishful thinking.

Air. Air in the filter makes a milky or sparkling cloud, erratic gauges, and a sight glass full of bubbles. An air-bound tank is not filtering; it is churning. Find the suction leak (lid O-ring, union, low waterline, equalizer), shut down, restart with a full basket chamber, and purge air per the manufacturer. Do not add more chlorine as the first move. You cannot oxidize a cloud that never reaches the media, and you can overshoot residual in a poorly mixed dead zone while the public still cannot see the floor.

Chemistry clouds, organics, clarifiers, and phosphates

When flow is real and media are clean, look at the test kit.

High pH weakens hypochlorous acid (Chapters 3 and 4) and can push calcium out of solution. A scaling CSI (Chapter 5: pH, total alkalinity, calcium hardness, temperature) makes a white calcium cloud or crust on tile and heaters. The fix is balance and filtration, not a second bag of calcium hypochlorite that raises pH further.

Organics—sweat, lotion, storm debris, pollen—consume sanitizer and scatter as fine particles. You need oxidation and filtration together. Shock without a working filter leaves a haze of dead material. Filter without residual leaves a haze that is still alive.

Clarifiers (polymers) and alum (aluminum sulfate) are coagulation and flocculation tools: they help small particles stick together so media can catch them. Conceptual rules, not a secret AFO recipe:

• They do nothing useful if circulation is dead or the filter is air-bound.
• Alum is pH-sensitive and can drop a floc to the floor if you shut the pump too soon. Vacuuming that blanket is a skill, not a party trick, and waste still has to go to a legal discharge.
• Follow the product Safety Data Sheet (SDS) and the AHJ. This guide will not invent a national alum dose table.

Phosphates are nutrients. Fill water, fertilizer runoff, and some bathers add them. Algae use them. Phosphate removers can lower a contributing food source. They are not a published NRPA legal limit, not a substitute for free chlorine, and not a magic number that guarantees sparkle. Chasing a parts-per-billion trophy while residual is 0.3 ppm is how you buy chemicals and keep a green pool.

Worked cloud: Monday 7:10 a.m., outdoor basin of about 80,000 gallons, drain not visible, filter influent gauge bouncing, air in the sight glass, free chlorine 2.0 ppm. The wrong move is superchlorinating to 10 ppm and opening at 11 because the kit looks fine. The right move is close, restore a sealed suction path, purge the tank, confirm steady gallons per minute, then reassess clarity and chemistry. Chlorine was never the missing first check.

Algae: types as a field ID, treatment as a program

Teach three conceptual field types. They are operator language, not a microbiology thesis, and NRPA does not publish a mandatory species list you must memorize as statute.

• Green algae. Water turns pea-soup or walls feel slick. Usually low residual, poor brushing, shady corners, or a filter that has been bypassing. Free-floating green often clears faster than attached slime once you brush and oxidize.
• Mustard (yellow) algae. Dusty yellow-brown film on walls, often in shade or on poorly circulated steps. It brushes off and returns if residual and brushing lapse. Check plastic floats, lane-line reels, and toys; they reseed the basin.
• Black algae. Dark spots rooted in plaster pores. Slow. Needs aggressive brushing, a sustained residual, and patience. It is not a one-hour copper job.

The program that actually works:

1. Brush every surface you can reach—walls, floor, ladders, behind ladders, tile line, spa benches. Chemicals do not replace mechanical removal of the film.
2. Restore a free-chlorine residual in the range your AHJ and product require. Dead algae still load the filter.
3. Shock or oxidize per Chapter 4 when combined chlorine or a bloom demands it. Keep brushing on the follow-up days.
4. Filter: backwash or clean often while the bloom dies. A packed tank returns green water to the basin. Know your media: vacuuming a heavy green load straight into a DE grid without a plan is how you drop cake and pass turbidity.

Copper (and other metals) can appear on algaecide labels. They are not the first answer on a public pool without AHJ and stain caution. Copper stains light plaster and hair. Some jurisdictions limit metallic algaecides. Metals plus a swinging pH become a Chapter 15 finish problem. If you use a metal product at all, it is an adjunct after brushing and residual, with SDS, compatible sanitizer chemistry, and a plan for staining—not a substitute for the program above.

Do not drain a green public pool as the first reflex. Draining raises hydrostatic, waste-discharge, and refill-balance problems you just studied in 16.1. Drain when the AHJ or a true renovation requires it, not because brushing felt like work. Chapter 12 already told you a heat-wave bloom is an in-season operations close if clarity fails. This section owns the recovery program after that close.

Combined-chlorine complaints versus insufficient free chlorine

Bathers say the pool smells like too much chlorine and their eyes burn. Operators sometimes believe them and turn the feeder down. Test free and total chlorine (Chapter 2). Combined chlorine = total − free (Chapter 4).

If free chlorine is 0.4 ppm and combined is 1.2 ppm, you do not have too much sanitizer. You have not enough free chlorine and a chloramine problem. Indoor air can make the smell worse (Chapter 12). The moves are: restore free chlorine, oxidize toward breakpoint as Chapter 4 taught, reduce organics, and fix ventilation if indoor—not a cyanuric-acid dump and not a feeder shutdown.

If free chlorine is already healthy and combined is low, look at air, locker rooms, or a product odor, not a panic shock.

Trap: add more chlorine on an air-bound or no-flow plant. You may raise residual in a poorly mixed dead zone while the main body stays cloudy and under-sanitized. Prove circulation first. Another trap: treating a combined-chlorine complaint as proof the feeder is too aggressive when the test kit shows free chlorine near zero.

Equipment faults: a decision tree, not a parts cannon

Use Chapter 7 anatomy and Chapter 8 maintenance language. Do not reprint pump curves here. Read gauges, valves, strainers, and interlocks.

No flow (motor humming or silent):

1. Power, breaker, thermal overload, emergency stop.
2. Strainer basket: clogged, missing, or lid leaking air.
3. Isolation valves: suction or return closed from yesterday's repair.
4. Water level below skimmer; lost prime.
5. Impeller obstruction—lock out before you open the volute (Chapter 8 / OSHA).

High pressure (influent up, flow down):

1. Dirty filter—backwash or clean; confirm laterals, grids, or cartridges.
2. Return path throttled or heater bypass mis-set.
3. Scale in laterals or the heat exchanger (CSI from Chapter 5).
4. Do not fix high pressure by dumping chlorine or by dead-heading the pump.

Heater not firing:

1. Flow or pressure switch—no proven flow, no burner. That is a safety interlock (Chapter 7), not a nuisance.
2. Fuel or power: gas cock, propane, breaker.
3. Ignition, high-limit, vent or air proving—licensed technician territory for gas.
4. Scale on the exchanger from off-season imbalance (16.1 opening). A heater that fires but does not raise temperature may be bypassing, scaled, or undersized for the load; still prove flow before you buy a new unit (Section 16.3).

Feeder not pumping:

1. Flow interlock off because the pump is off or the paddle is stuck.
2. Empty tank, closed drum valve, crystallized suction.
3. Worn peristaltic tube or lost prime.
4. Controller already satisfied—or a lying probe (Chapter 14).
5. Never mix leftover vendors into one day tank to make it pump. Compatibility is a purchasing rule in 16.3 and a safety rule in Chapter 11.

Worked equipment miss: Saturday, 95°F, returns weak, filter pressure high, operator dumps two bags of shock because the water looks dull. The tank needed a backwash and a strainer clean. Two hours later residual is wild, combined chlorine is up from the organic load that never got filtered, and the drain is still a rumor. The first three checks were mechanical. Chemistry was the fourth conversation.

Symptom versus first three checks

That table is a field order, not an NRPA statute. If any step requires opening a pressurized vessel or a gas train, lock out and stay inside your license. Adding more chlorine does not unstick a closed valve, reseat an O-ring, or make an air-bound filter start filtering.