Pool Chemical Starter Guide: Which Chemicals You Actually Need and Which Ones Are a Waste of Money

Stop Wasting Money on Pool Chemicals: What You Actually Need (And What You Don’t)

Walk into any pool supply store and you’ll face an overwhelming wall of bottles, buckets, and powders — each one promising crystal-clear water and a perfectly balanced pool. The truth? Pools don’t require many chemicals, and certainly not everything you see on the pool shelf in stores. If you’re a new pool owner — or just tired of spending a fortune every summer — this guide cuts through the noise and tells you exactly what to buy, what to skip, and why.

At Backyard Supplies, a Long Island-based outdoor living retailer whose founders bring over 20 years of combined experience in the pool, spa, and outdoor living industry, the philosophy is simple: they know which products hold up and where homeowners usually get burned — and that knowledge goes into every product they carry and every conversation they have. That same straight-talk approach inspired this guide. You can browse their full selection of pool chemicals and supplies to stock up on exactly what your pool needs — nothing more, nothing less.

The Chemicals You Actually Need

Every pool needs six core chemicals to stay clean and safe: a chlorine sanitizer, pH increaser, pH decreaser, total alkalinity increaser, cyanuric acid (stabilizer), and calcium hardness increaser. Add pool shock to that list and you have a complete starter kit. Here’s what each one does:

  • Chlorine (Sanitizer): Chlorine is the main sanitizer for most residential pools. It kills bacteria, controls contaminants, and helps prevent algae. It is commonly sold as chlorine tablets, liquid chlorine, and granular chlorine. Liquid chlorine is cheaper than other forms but has a shorter effective period and requires more frequent application. Trichlor is a stabilized form that can withstand ultraviolet rays and is available in tablet form, making application easy.
  • pH Increaser & pH Decreaser: pH chemicals like pH Increaser and pH Reducer are used to adjust pH to the 7.2–7.4 range. Keeping pH in this sweet spot ensures your chlorine works efficiently and protects swimmers from irritation.
  • Total Alkalinity Increaser: Total alkalinity (TA) is the buffer that keeps pH from swinging up and down. The target is 80 to 120 ppm. Low alkalinity means your pH will be unstable and hard to hold.
  • Cyanuric Acid (Stabilizer): Cyanuric acid protects chlorine from being destroyed by UV sunlight. Without it, direct sun can burn off most of your free chlorine within a few hours. The target range is 30 to 50 ppm. Below 20 ppm, you are burning through chlorine and money.
  • Calcium Hardness Increaser: Calcium hardness measures how much dissolved calcium is in the water. Target 200 to 400 ppm for plaster and gunite pools, and 175 to 225 ppm for vinyl and fiberglass. Water that is too soft is aggressive — it will etch plaster and leave white calcium deposits on your equipment.
  • Pool Shock: Shock is a high-dose oxidizer treatment that burns off chloramines — the combined chlorine that causes that harsh chemical smell and eye irritation — kills algae, and resets the water after heavy use or rain. Shock after every big pool party, after heavy rain, and at least once every week or two during the swim season.

One Thing You Should Never Skip: Testing

Balance total alkalinity first, then adjust pH, then address calcium hardness and cyanuric acid. Add shock last and always with the pump running. Test your water with a reliable test kit or strips twice a week. Skipping this step is one of the most common — and costly — mistakes new pool owners make.

The Chemicals That Are Mostly a Waste of Money

Here’s where the pool industry loves to upsell you. These products aren’t inherently bad, but most pools simply don’t need them as a routine purchase:

  • Phosphate Removers: Phosphates are algae food, but if you maintain proper chlorine levels, algae cannot grow regardless of phosphate count. Save your money unless you’re dealing with a persistent, recurring algae problem that has been directly tied to high phosphate levels.
  • Algaecide (for most pools): Chlorine alone handles most algae prevention when levels stay between 1 and 3 ppm. Algaecide is a useful backup for pools in heavy shade or with recurring algae problems, but it is not required if your chlorine is consistently maintained. In fact, some may even be more harmful than helpful — any product that has copper can have long-term negative effects like staining that is extremely difficult to remove.
  • Clarifiers & Flocculants: Clarifier is used for mildly cloudy or hazy water. It works by binding very small particles together so the filter can catch them more easily. If chlorine, pH, or filtration is off, fix those first. Flocculants bind particles together so they sink to the bottom to be vacuumed. Like clarifiers, a balanced pool will never need floc treatments.
  • Enzyme Treatments: Enzyme treatments break down oils, sunscreen, body residue, and other organic waste. They are most useful in heavily used pools or pools with oily buildup and scum lines. They help reduce organic residue, but they do not sanitize the water and do not replace chlorine. For the average backyard pool, they’re a nice-to-have, not a need-to-have.

A Few Safety Rules to Always Follow

No matter which chemicals you use, safe handling is non-negotiable:

  • Do not shock during the day; add shock at dusk instead.
  • Cross-contamination of different chlorine types can release toxic chlorine gas and trigger fires and explosions. They can also cause severe health problems, including chemical burns. Never mix or store different types of chlorine together.
  • Storage for your pool chemicals is important not only for safety reasons but also to prolong the overall effectiveness of each chemical. They should be stored in a cool, dry, well-ventilated area, preferably away from other household chemicals and flammable items.

The Bottom Line

If you just filled a new pool or you are taking over one and have no idea where to start, the chemical aisle at any pool store can feel overwhelming. Dozens of products, most of them doing roughly the same thing under different names. But now you know the truth: a handful of essential chemicals, a good test kit, and a consistent routine is all it takes to keep your pool sparkling all season long. Don’t let flashy marketing convince you otherwise — your wallet (and your pool) will thank you.

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