Last updated: April 1, 2026 — all prices and product specs verified today
Pool chemical aisles are designed to sell you things you may not need. Dozens of products with different names, different claims, and significantly different prices — most of which address problems you either do not have or could prevent with basic chemistry management. This guide tells you what every pool owner genuinely needs, what is optional for specific situations, and what is a waste of money for most pools.
QUICK ANSWERS
Q: What pool chemicals do I need every season?
A: Five categories cover every pool: (1) sanitizer — chlorine tablets or liquid chlorine, (2) shock — cal-hypo at 68%, (3) algaecide — polyquat 60, (4) pH adjuster — sodium bisulfate to lower, soda ash to raise, (5) total alkalinity increaser — sodium bicarbonate. Everything else is situational. Buy these five first.
Q: What is the correct order to add pool chemicals?
A: Always: (1) total alkalinity first, (2) pH second, (3) calcium hardness if needed, (4) shock last. Never add two chemicals at the same time. Allow the pump to run for at least 4-6 hours between additions so each chemical fully circulates before the next one is added.
Q: How much does it cost to maintain a pool for a full season?
A: For a 20,000-gallon inground pool: $278-417 in chemicals per season when buying in bulk from a direct pool supply source. The same chemicals purchased at retail hardware stores cost $400-600+. The largest single savings is switching from retail 5-lb chlorine tablet packs ($5.60-7.00/lb) to a direct-supply 50-lb bucket ($2.00-2.60/lb).
Q: What is the difference between sanitizer and shock?
A: Sanitizer — chlorine tablets — maintains a steady 1-4 ppm free chlorine baseline that prevents bacterial growth under normal conditions. Shock temporarily raises free chlorine to 10-30 ppm to destroy chloramines, kill algae, and address problems that baseline sanitizer cannot handle. Both are needed. Neither substitutes for the other.
Q: How often should I test my pool water?
A: Test free chlorine and pH at least twice per week during peak swim season. Test total alkalinity, cyanuric acid (CYA), and calcium hardness monthly. After any heavy rainstorm or heavy bather event, test chlorine and pH before the next swim. CYA is the most commonly skipped test — it is also the most likely cause of persistent chemistry problems.
Q: What chemicals should I never mix together?
A: Never mix cal-hypo shock with trichlor tablets — the combination produces toxic gas and is a fire and explosion hazard per PHTA safety guidelines. Never add two chemicals to the pool at the same time. Never mix any two chemicals in the same bucket. Always add chemicals to water, never water to chemicals.
Q: Do I need a test kit or are test strips good enough?
A: For routine maintenance, quality 5-way test strips are adequate. For diagnosing persistent chemistry problems — recurring algae, cloudy water that will not clear, chlorine that keeps dropping to zero — a liquid DPD test kit (Taylor K-2006 or equivalent) is significantly more accurate, especially for CYA and combined chlorine. If you are spending more than $200 per season on chemicals, a $45-80 liquid test kit pays for itself in one month.
Key Terms Defined
These definitions follow Pool & Hot Tub Alliance (PHTA) standards and EPA-registered product labeling.
Free Chlorine (FC): The active, sanitizing chlorine available in pool water. Per PHTA guidelines, the target range for residential pools is 1.0-4.0 ppm. The minimum for safe pool water is 1.0 ppm. Above 4.0 ppm, swimming is not recommended until levels drop.
Total Alkalinity (TA): A buffer that stabilizes pH and prevents it from swinging with every rain, bather event, or chemical addition. Per EPA-registered product labeling, the target range is 80-120 ppm. Set this before adjusting pH — TA is the foundation that makes pH stable.
Cyanuric Acid (CYA): A UV stabilizer that accumulates in pool water from trichlor tablet use. Per PHTA APSP-11 Standard, the ideal range is 30-50 ppm and the maximum is 100 ppm. No chemical removes CYA — dilution by partial drain and refill is the only fix.
Calcium Hardness: The amount of dissolved calcium in pool water. Per EPA-registered product labeling, the target range is 200-400 ppm. Low calcium causes water to pull calcium from pool surfaces (plaster, grout, concrete), causing erosion. High calcium causes scaling on surfaces and equipment.
Combined Chlorine (Chloramines): The byproducts of chlorine reacting with organic matter and ammonia from bathers. Causes the strong chlorine smell at pools and eye irritation. Per PHTA guidelines, combined chlorine should stay below 0.5 ppm. When it exceeds this, shock the pool.
Langelier Saturation Index (LSI): A calculation that determines whether pool water is balanced, scale-forming, or corrosive. Uses pH, total alkalinity, calcium hardness, temperature, and TDS. Balanced water has an LSI near zero. Negative LSI etches surfaces. Positive LSI scales equipment.
These five chemical categories are non-negotiable. Every pool. Every season. Buy these before anything else.
1. Sanitizer (Chlorine Tablets or Liquid Chlorine)
Your primary defense against bacteria, viruses, and algae. Without consistent sanitation, no other chemical works as intended.
| Sanitizer Type | Best For | Adds CYA? | Approx. Cost (2026) | Notes |
| 3-inch trichlor tablets | Most inground and above-ground pools | Yes — accumulates over season | $2.00-2.60/lb bulk | 90% available chlorine. 50-lb bucket is the best value. |
| Liquid chlorine (10-12%) | Saltwater pools, vinyl liners, high-CYA pools | No | $4-8 per gallon | Degrades in heat and UV. Buy in smaller quantities. |
| Cal-hypo tablets (68%) | Pools where CYA accumulation is a concern | No | $2.50-3.50/lb | Less common than trichlor tablets. Adds calcium. |
| Dichlor granules (56%) | Spas, hot tubs, pools with low CYA needing a boost | Yes — 6-7 ppm per lb per 10k gal | $3-5/lb | Near-neutral pH. Fast dissolving. Use situationally. |
Source: PHTA free chlorine standard 1.0-4.0 ppm; trichlor 90% available chlorine standard
Bottom Line: For most inground pools, 3-inch trichlor tablets in a 50-lb bulk bucket are the correct choice. The chemistry is EPA-standardized at 90% available chlorine across all brands. The price difference between retail and bulk is $65-100 per season on identical chemistry.
2. Shock (Calcium Hypochlorite)
Weekly or bi-weekly oxidation burns out chloramines, handles organic load, and addresses any algae before it establishes. Cal-hypo at 68% formulation (65% available chlorine) is the standard for most pools.
Buying in a 24-bag case drops the per-pound cost to roughly half of what individual bags cost at retail. For a pool shocking weekly through a 20-week season, that is 20 bags minimum — a case purchased at opening is both the practical and economical choice.
Source: PHTA Cal-Hypo Fact Sheet 2021 — product characteristics, safe swimming reentry at 4.0 ppm or less
3. Algaecide (Polyquat 60)
Algaecide is maintenance chemistry — it keeps algae from establishing when used consistently. It is not rescue chemistry. Once algae is visibly green in your pool, algaecide alone will not clear it. Shock clears green water. Algaecide prevents green water from returning.
Add polyquat 60 algaecide weekly during the swim season, particularly after heavy rainstorms. A quart of polyquat 60 lasts most of a swim season and costs $15-25. That is cheap insurance against a green pool that would cost $150-400 to treat.
✓ KEY FACT: Add algaecide only after free chlorine drops below 4 ppm. Quat and polyquat algaecides are chemically deactivated by high chlorine levels. Adding algaecide immediately after shocking means the product is destroyed before it reaches any algae.
4. pH Adjuster
pH controls how effective every other chemical is. In unstabilized pools, chlorine at pH 8.0 operates at approximately 20% efficiency versus 63% at pH 7.2. In stabilized pools using trichlor tablets (most residential pools), the FC:CYA ratio has a greater influence on chlorine effectiveness than pH — but maintaining pH in the 7.2-7.8 range is still essential for equipment protection, LSI balance, and swimmer comfort.
| Product | Chemical Name | Use | Typical Dose | Approx. Cost |
| pH decreaser (pH Down) | Sodium bisulfate (dry) or muriatic acid (liquid) | Lower pH when above 7.6 | 1 lb sodium bisulfate per 10,000 gal drops pH ~0.4 units | $18-28 per 10 lbs |
| pH increaser (pH Up) | Sodium carbonate (soda ash) | Raise pH when below 7.2 | 6 oz per 10,000 gal raises pH ~0.2 units | $10-18 per 5 lbs |
✓ KEY FACT: pH trends upward naturally in most pools due to aeration, bather activity, and the chemistry of trichlor tablet dissolution. Buy more pH decreaser than you think you need — it goes faster than most pool owners expect. A 10-lb bag is a reasonable opening purchase.
Source: PHTA Water Balance Fact Sheet — acceptable pH range 7.2-7.8; LSI calculation factors
5. Total Alkalinity Increaser (Sodium Bicarbonate)
Set total alkalinity correctly at opening and it typically needs minimal adjustment through the season. Sodium bicarbonate raises TA. Muriatic acid or sodium bisulfate lower it — the same products that lower pH also lower TA, so they do double duty.
Dosing: Raising Total Alkalinity with Sodium Bicarbonate
Standard dose: 1.5 lbs sodium bicarbonate per 10,000 gallons raises TA by ~10 ppm
Example: 20,000-gallon pool, current TA 60 ppm, target 100 ppm
Increase needed: 40 ppm
Calculation: (40 / 10) x (20,000 / 10,000) x 1.5 lbs = 12 lbs
Add in two doses of 6 lbs each, 4 hours apart.
Retest before adding second dose.
Note: ARM & HAMMER baking soda is identical chemistry to pool store
‘alkalinity increaser’ — typically at 3-5x lower cost per pound.
The Optional Chemicals: Useful in Specific Situations
These products address real problems — but only if you have those specific problems. Most pools do not need all of them.
Cyanuric Acid (Stabilizer / Conditioner)
If you are opening a freshly filled pool or have done a large partial drain, CYA may be low (below 20 ppm). Adding cyanuric acid directly brings CYA to the 30-50 ppm target range immediately rather than waiting weeks for trichlor tablets to build it up.
⚠ WARNING: Do NOT add CYA if you do not know your current level. Test first. Adding CYA to a pool already at 50-60 ppm pushes it toward the problematic range. Over-stabilization is far more common than under-stabilization in pools using trichlor tablets. The only fix for high CYA is a partial drain.
Source: PHTA APSP-11 Standard — CYA ideal range 30-50 ppm, maximum 100 ppm
Clarifier
Clarifier works by aggregating tiny suspended particles that are too small for your filter to catch into larger particles the filter can remove. Useful for post-opening cloudiness that is not algae-related, polishing slightly hazy water after a heavy bather event, and speeding up filtration after a major shock treatment.
Not useful for cloudiness caused by algae (shock and algaecide are needed), high calcium hardness (test and address the source), or chemical imbalance. Clarifier does not fix the cause of cloudiness — it helps the filter catch the particles faster once the underlying issue is addressed.
Phosphate Remover
Phosphates are algae food. Levels above 200-500 ppb can fuel aggressive algae growth even when chlorine appears adequate. Phosphates enter pools through tap water, rain runoff, fertilizer near the pool, and decomposing organic matter.
Testing for phosphates is worth doing if you fight recurring algae despite maintaining correct chemistry. Most pools with consistent chemical management and weekly shocking do not develop phosphate problems. Test before buying the product — phosphate removers are $20-40 per quart and address a problem many pools do not have.
Calcium Hardness Increaser (Calcium Chloride)
Relevant for pools in areas with naturally soft water. Low calcium hardness below 150 ppm causes water to become corrosive — it pulls calcium from pool surfaces to satisfy its demand. Concrete, plaster, and grout erode faster. Equipment seals and metal components corrode.
For pools filled with naturally soft water, testing and adjusting calcium hardness at opening is worthwhile. Calcium chloride raises hardness quickly and is inexpensive. The standard dose is approximately 1.25 lbs per 10,000 gallons to raise hardness by 10 ppm.
Metal Sequestrant
Relevant almost exclusively for pools filled with well water or pools where copper-based algaecides have been used. Metal sequestrants prevent dissolved metals from precipitating out of solution and staining pool surfaces.
For pools filled with municipal water and using only non-copper algaecides, metal levels are typically low enough not to cause staining. Do not buy this product without testing for metals first. A metal test strip ($5-10) tells you whether you need a sequestrant before spending $15-25 on the product.
Non-Chlorine Shock (Potassium Monopersulfate)
An oxidizer, not a sanitizer. Cannot kill algae or bacteria. Useful for pre-swim oxidation before a pool party — reduce the organic load so your regular chlorine can focus on sanitizing during heavy use. Allows swimming 15 minutes after application. See our Pool Shock Guide for full details on when to use non-chlorine vs. chlorine-based shock.
What You Probably Do Not Need
These products are widely sold but solve problems most pool owners do not have, or address issues better handled by correct basic chemistry.
| Product | What It Claims | The Reality | When It’s Actually Useful |
| Pool enzymes | Break down oils, sunscreen, and organic compounds | Weekly cal-hypo shock does the same thing at a fraction of the cost. Enzymes add $50-100/season for minimal additional benefit in normally maintained pools. | Pools with unusually heavy organic load — leaf debris, heavy wildlife, pools near pine trees |
| Weekly maintenance kits (big-box bundles) | One-stop chemical package for the week | Pre-packaged kits include products you may not need at dosages designed for average conditions that may not match yours. Testing first and adding only what is needed costs less and works better. | Never — test first, then treat specifically |
| Metal sequestrant (preventive) | Prevents metal staining before it happens | Municipal water contains minimal metals. Without well water or copper algaecides, there is nothing to sequester. | Well water fills, copper-based algaecide users, pools with iron staining history |
| Algae prevention products beyond polyquat 60 | ‘Guaranteed to prevent algae all season’ | Polyquat 60 plus consistent shocking handles algae prevention in virtually all residential pools. Additional algae products are redundant when basics are right. | Black algae in plaster pools — this is a specific situation where specialty products help |
Bottom Line: Every dollar you spend on specialty products beyond the core five is a dollar that could go toward a higher-quality test kit, a larger bulk purchase of the chemicals you actually need, or simply staying in your pocket. Fix the basics first. Most pool chemistry problems are caused by incorrect pH, untested CYA, or inconsistent sanitation — not a missing specialty product.
The Correct Order to Add Pool Chemicals
Adding chemicals in the wrong order either wastes them or creates dangerous reactions. This sequence applies to opening a pool, correcting chemistry after a test, and any routine adjustment.
| Step | Chemical | Why This Order | Wait Before Next Step |
| 1 | Total alkalinity (sodium bicarbonate) | TA is the pH buffer. Set this first so pH adjustments are stable. | 4-6 hours, retest TA |
| 2 | pH (sodium bisulfate or soda ash) | pH controls how effective every other chemical is. Must be in range before shocking. | 4-6 hours, retest pH |
| 3 | Calcium hardness (calcium chloride) | Rarely needs adjustment. Add only if testing confirms below 200 ppm. | 4-6 hours, retest hardness |
| 4 | Cyanuric acid (stabilizer) | Add only if testing confirms below 20 ppm. Do not add if CYA is already in range. | 24-48 hours for granular CYA to fully dissolve |
| 5 | Shock (cal-hypo) | Add last, after sunset, after all other parameters are balanced. Pre-dissolve in a bucket. | Run pump overnight 8+ hours |
| 6 | Algaecide (polyquat 60) | Add morning after shocking, once FC drops below 4 ppm. | Ongoing maintenance |
⚠ WARNING: Never add two chemicals at the same time. Never mix two chemicals in the same bucket. Never add water to dry chemicals — always add dry chemicals to water. The reaction from adding water to calcium hypochlorite can cause spattering of caustic material.
Building Your Full Season Chemical Budget
For a 20,000-gallon inground pool through a full swim season. All prices reflect April 2026 direct pool supply source pricing.
| Chemical | Quantity Needed | Direct Supply Cost | Retail Hardware Store Cost |
| Chlorine tablets (50 lb bulk) | 50-75 lbs | $100-155 | $280-420 |
| Cal-hypo shock 68% (24-bag case) | 1-2 cases | $75-110 per case | $120-150 per case |
| Algaecide polyquat 60 (qt) | 2 quarts | $30-50 | $50-70 |
| pH decreaser (10 lbs) | 10 lbs | $18-28 | $30-40 |
| pH increaser (5 lbs) | 5 lbs | $10-18 | $15-25 |
| Alkalinity increaser (10 lbs) | 10 lbs | $10-18 | $18-28 |
| Liquid test kit (Taylor K-2006) | 1 kit (lasts 2+ seasons) | $45-80 | $55-90 |
| Total | $278-429 | $558-798 |
Bottom Line: A pool owner buying the standard seasonal chemical supply from a direct pool supply source versus retail hardware stores saves $280-370 per season on identical chemistry. Over 10 years of pool ownership, that is $2,800-3,700 in savings with no change in product quality or pool water chemistry.
The Real Cost of Retail vs. Direct Supply Pricing
The active ingredients in pool chemicals are standardized commodities regulated by the EPA. The chemistry in a $35 5-lb bucket of chlorine tablets from a hardware store is identical to the chemistry in a $130 50-lb bucket from a direct pool supply source. What you pay extra for at retail is shelf space, smaller pack sizes, and seasonal demand markup.
| Product | Retail Price Per Unit | Direct Supply Price Per Unit | Annual Savings |
| Chlorine tablets (per lb) | $5.60-7.00/lb (5-lb retail) | $2.00-2.60/lb (50-lb bulk) | $65-100 on 50 lbs |
| Cal-hypo shock (per lb) | $6.00-9.00/lb (individual bags) | $3.10-4.60/lb (24-bag case) | $40-75 per season |
| Algaecide (per quart) | $25-35/qt | $15-22/qt | $10-26 per season |
| pH decreaser (per lb) | $3.00-4.00/lb (retail) | $1.80-2.80/lb (bulk) | $12-22 per season |
| Total annual savings | $127-223 per season |
10-Year Savings: Retail vs. Direct Supply
Average annual savings buying direct: $175 (midpoint of $127-223 range)
Over 10 years: $1,750
Over 20 years (typical pool lifespan): $3,500
The chemistry is EPA-standardized and identical across sources.
The only difference is where you buy it.
If X Happens, Do Y: Troubleshooting Chemical Problems
Why is my chlorine dropping to zero every day?
Four causes in order of likelihood:
- CYA above 80 ppm — the chlorine is present but locked up and less effective. Test CYA before adding more chemicals. If above 80 ppm, partial drain and refill before re-treating.
- Active algae consuming chlorine faster than tablets replace it — shock at 3-5 lbs per 10,000 gallons after brushing all surfaces, then address the underlying chemistry.
- Heavy organic load — high bather use, decomposing debris, or high phosphates creating high chlorine demand. Shock weekly and keep skimmer baskets and filter clean.
- Extremely hot water above 90 degrees F — chlorine demand increases and tablets dissolve faster. Increase tablet count slightly and shock more frequently.
Why does my pH keep rising even after I add pH decreaser?
High total alkalinity. TA above 120 ppm acts as a strong pH buffer — it resists acid additions and pushes pH back up. The fix is to lower TA first using the acid addition method:
- Add muriatic acid or sodium bisulfate to lower both pH and TA together
- Turn off the pump and allow the acid to concentrate near the bottom
- Aerate the water (run fountains, return jets pointed up) to off-gas CO2 and raise pH back without raising TA
- Repeat until TA is in the 80-100 ppm range — pH will become stable
Why does my pool smell like chlorine even though my chlorine level reads fine?
The smell is from combined chlorine (chloramines), not free chlorine. Test total chlorine and free chlorine. The difference between the two readings is combined chlorine. If combined chlorine is above 0.5 ppm per PHTA guidelines, shock the pool. The strong ‘chlorine smell’ at a pool is a sign the chlorine is being consumed and forming chloramines — the opposite of what most people assume.
Why is my pool water green but my chlorine reads normal?
High CYA. Above 80 ppm, cyanuric acid substantially reduces chlorine effectiveness even when the test kit reads a normal free chlorine level. The test measures chlorine present — not how much of it is biologically available to kill algae. Test CYA. If above 80 ppm, drain 1/3 to 1/2 of pool volume and refill before adding any more chemicals.
Why is my pool water cloudy after I added chemicals?
Temporary cloudiness after cal-hypo shock is normal and typically clears in 12-24 hours as the filter removes dead organic matter and fine particles. Persistent cloudiness has one of three actual causes:
- High calcium hardness above 400 ppm — calcium precipitating out of solution. Test hardness. If elevated, partial drain.
- Poor filtration — filter clogged or dirty. Backwash sand or DE filter. Clean cartridge.
- Chemical addition order was wrong — adding shock before pH was balanced can cause precipitation. Drain is rarely needed, but patience and continuous filtration resolve it over 48-72 hours.
Is it safe to mix pool chemicals to save time?
No. Never mix two pool chemicals together before adding them to the pool, even if they are both going into the water in the same session. Adding chemicals to water separately is safe. Combining chemicals before adding them can produce violent reactions, toxic gas, and heat. The most dangerous common combination is cal-hypo shock and trichlor tablets — the two most widely used pool chemicals — which produce toxic chlorine gas and are a fire and explosion hazard per PHTA safety documentation.
⚠ WARNING: NEVER mix cal-hypo shock and trichlor tablets in the same container, bucket, or storage space. Both are standard pool chemicals. Their combination is a documented fire and explosion hazard per PHTA/APSP safety guidelines.
Source: PHTA/APSP Trichlor Fact Sheet — incompatibility with other chlorinating agents
10 Buyer Questions Answered
What pool test kit do professionals actually use?
The Taylor K-2006 complete test kit is the industry standard for residential pool care professionals. It uses FAS-DPD liquid reagents that are significantly more accurate than test strips for free chlorine, combined chlorine, pH, total alkalinity, calcium hardness, and CYA. Cost: $45-80 for the standard configuration with 0.75 oz reagent bottles. It lasts 2+ seasons with normal use. The K-2006 is the kit that pool service technicians carry — not test strips.
Can I use baking soda instead of pool alkalinity increaser?
Yes. Standard ARM & HAMMER baking soda (sodium bicarbonate) is chemically identical to pool store ‘alkalinity increaser.’ The pool store version typically costs 3-5x more per pound. The only meaningful difference is packaging. Buy in bulk grocery quantities or a large box from a warehouse store for the same result at a fraction of the price.
What happens if I forget to add chemicals for a week?
Depends on conditions. In cool, overcast weather with light use, a week without chemical attention may result in only minor pH drift and slight chlorine depletion. In hot, sunny weather with heavy bather load, a week without attention can result in chloramine buildup, algae establishment, and significant pH drift. Test everything before swimming. Shock if combined chlorine is above 0.5 ppm per PHTA guidelines. Adjust pH if outside the 7.2-7.8 range. Do not skip testing and assume the water is fine.
Are store-brand pool chemicals as good as name brands?
For the standardized chemicals — trichlor tablets (90% available chlorine), cal-hypo shock (65% or 70% available chlorine), sodium bisulfate, sodium bicarbonate — the chemistry is EPA-regulated and identical across brands. Quality differences exist in compression density for tablets (affects dissolution rate) and filler content (affects active ingredient per ounce). For a brand like Doheny’s that specifies no fillers, 99% active ingredient, and US manufacturing, you are paying for confirmed quality specs, not for a premium on the chemistry itself.
How do I know if my test kit is giving me accurate readings?
Three indicators of inaccurate readings: (1) test results that contradict visible pool conditions (reads fine but pool is green), (2) reagent bottles that are more than two years old or were stored in heat, (3) test strips that were exposed to moisture or humidity. Replace reagents annually. Store test kits in a cool, dry location. If readings seem wrong, take a water sample to a pool store for a free electronic water test and compare — most major pool retailers offer this service.
What chemicals do I need to close my pool for winter?
The core closing chemicals: (1) shock at 2x the normal dose the night before closing, (2) algaecide added after chlorine drops below 4 ppm, (3) pH adjusted to 7.2-7.6, (4) TA adjusted to 80-120 ppm, (5) winterizing algaecide specifically formulated for extended protection if closing for 6+ months. For pools in freezing climates, also add pool antifreeze to plumbing lines after blowing them out.
Can I use household bleach to sanitize my pool in an emergency?
Yes, but it is impractical for ongoing maintenance. Pool-grade liquid chlorine is 10-12.5% sodium hypochlorite. Household bleach is 1.5-6% sodium hypochlorite. To raise free chlorine by 1 ppm in a 20,000-gallon pool using 3% household bleach requires approximately 5 gallons. For an emergency situation where no pool supplies are available, household bleach works. For routine pool maintenance, use pool-grade products.
Should I use a saltwater system to avoid buying chemicals?
Saltwater pools still require chemicals — they are not chemical-free. A salt chlorine generator produces chlorine from dissolved salt, which reduces the need for tablet or liquid chlorine purchases. However, saltwater pools still require: pH adjustment (salt systems raise pH continuously), shock periodically, algaecide, alkalinity management, and CYA to protect the generated chlorine from UV. Salt systems reduce chemical costs by roughly 30-50% and eliminate the need to handle concentrated chlorine — but they do not eliminate pool chemistry.
What is the lowest-cost way to maintain a clear pool all season?
Buy in bulk at the start of the season. Specifically: a 50-lb bucket of chlorine tablets ($100-130), a case of 24 cal-hypo shock bags ($75-110), and two quarts of polyquat 60 algaecide ($30-50). Add a liquid test kit ($45-80) if you do not have one. Test twice weekly. Shock weekly. Add algaecide weekly. Address pH and TA as needed. Total season cost under $300 for a 20,000-gallon pool. That is the complete answer.
What pool chemical has the highest markup at retail?
Chlorine tablets, by a significant margin. The 5-lb retail bucket at $28-35 works out to $5.60-7.00 per pound. The 50-lb direct supply bucket at $100-130 works out to $2.00-2.60 per pound. That is a 2.5-3.5x markup for identical chemistry — trichloro-S-triazinetrione at 90% available chlorine, standardized by the EPA. The retail premium reflects pack size and shelf space costs, not product quality. Buying the 50-lb bucket is the single most impactful purchasing decision a pool owner makes each season.
Where to Buy Pool Chemicals
Doheny’s Pool Supplies carries the full range of season chemicals — chlorine tablets, cal-hypo shock, polyquat algaecide, pH adjusters, and alkalinity increaser — with free shipping on orders over $50 and a lowest price guarantee. Family owned since 1967. Next-day delivery available on Doheny’s brand chemicals to most of the continental US. Shop Doheny’s pool chemicals →
The highest-leverage order at the start of the season: one 50-lb bucket of chlorine tablets, one case of cal-hypo shock, two quarts of polyquat 60, and a 10-lb bag of pH decreaser. That covers most of what you need for a full season before you have tested a single water sample. See our Where to Buy page for direct links and current April 2026 pricing.
External References
PHTA Cal-Hypo Fact Sheet 2021 — free chlorine standard 1.0-4.0 ppm; 68% cal-hypo characteristics: https://www.phta.org/pub/?id=07fd3498-1866-daac-99fb-8824a8f3147b
PHTA Trichlor Fact Sheet — 90% available chlorine standard; incompatibility with other chlorinating agents: https://www.phta.org/pub/?id=09389576-1866-daac-99fb-f58144f4f5df
PHTA Water Balance Fact Sheet 2022 — CYA ideal range 30-50 ppm; APSP-11 maximum 100 ppm; pH range; LSI: https://www.phta.org/pub/?id=50ffe77d-1866-daac-99fb-9719108d1367
PHTA Liquid Chlorine Fact Sheet — sodium hypochlorite for all pool types; UV degradation: https://www.phta.org/pub/?id=0905861a-1866-daac-99fb-b239bf43994b
PHTA/APSP Dichlor Fact Sheet — 56% and 62% available chlorine; two formulations; CYA addition: https://www.phta.org/pub/?id=08fa1535-1866-daac-99fb-f5e639fbe1c0
Pool Help (Pickens 2017) — pH and chlorine efficacy in stabilized vs. unstabilized pools: https://www.poolhelp.com/home/onbalance-research/onbalance-research/the-true-science-about-ph-chlorine-efficacy/
US Poison Control Center: 1-800-222-1222 — https://www.poison.org