Water ChemistryHow-to
How to Lower Chlorine in a Pool
Chlorine reading high? Make sure the test isn't lying, stop whatever is feeding it, and let the sun do the work. When a neutralizer is worth using.
10 minUpdated Sep 27, 2026
Topic
Pool Water Testing Guides
Every good decision about your water starts with an accurate test. Most bad ones start with a strip.
15 guides on this topic
Spas & Hot TubsExplainer
Hot Tub Rash: Why It Happens
It is a water problem before it is a skin problem. What lets the bacteria survive a hot tub, and the sanitizer habits that stop it recurring.
5 minUpdated Sep 8, 2026
Water ChemistryExplainer
How Long After Shocking a Pool Can You Swim?
The honest answer is not a number of hours. It is a chlorine reading — and knowing which one saves you a day of waiting or an evening of stinging eyes.
6 minUpdated Sep 8, 2026
Water ChemistryExplainer
Calcium Hardness: The Number That Only Goes Up
Too low and the water eats your plaster. Too high and it scales everything. Targets by surface, how to raise it, and why lowering it means draining.
5 minUpdated Sep 6, 2026
Spas & Hot TubsTroubleshooting
Cloudy Hot Tub Water and Foam: What Actually Causes Both
Why hot tubs foam and why they go cloudy, from the spa makers' own manuals, and how to find which cause you have before you buy another bottle of something.
6 minUpdated Oct 1, 2026
Spas & Hot TubsGuide
Hot Tub Water Chemistry: Targets and Sanitizers
Bromine versus chlorine in a spa, the target ranges that differ from a pool, and why 400 gallons at 102 degrees is a completely different problem.
8 minUpdated Oct 1, 2026
Water ChemistryExplainer
Phosphates in Pool Water: When They Actually Matter
Phosphates feed algae, but a high reading is not why your pool went green. What the number means and when removing it is money well spent.
5 minUpdated Sep 6, 2026
Water ChemistryTroubleshooting
Pool Stains: How to Identify and Remove Every Type
Metal stains, organic stains and scale all look similar and need completely different treatments. Here's how to tell them apart.
5 minUpdated Jul 9, 2026
Water ChemistryExplainer
Langelier Saturation Index: What LSI Means and How to Fix It
Why two pools with identical test results behave completely differently, and how the saturation index ties all your numbers together.
5 minUpdated Aug 12, 2026
GuidesHow-to
How to Test Pool Water (And Why Strips Mislead You)
Sampling technique, which test kit to buy, what to test how often, and the reading errors that send people chasing problems they don't have.
5 minUpdated Sep 13, 2026
Water ChemistryExplainer
Free vs Total Chlorine: What the Numbers Actually Mean
That strong chlorine smell means you don't have enough chlorine, not too much. Here's what free, combined and total chlorine each tell you.
5 minUpdated Sep 13, 2026
ReviewsBuying guide
The Best Pool Test Kits in 2026
Real models and real prices. Why a $150 drop kit beats a $20 box of strips, and what each one can and cannot actually measure.
6 minUpdated Sep 12, 2026
Water ChemistryExplainer
Total Alkalinity vs pH: Why Your pH Won't Stay Put
If you're adding acid every three days, you don't have a pH problem. Here's what alkalinity actually does and how to stop chasing the number.
5 minUpdated May 19, 2026
Water ChemistryExplainer
Cyanuric Acid in Pools: Ideal CYA Levels and How to Lower It
What CYA actually does to your chlorine, why 30-50 ppm is the sweet spot, and how to bring it down when tablets have run it up to 100.
7 minUpdated Oct 1, 2026
Water ChemistryGuide
How to Balance Pool Chemistry: Order, Targets and Timing
The five numbers that matter, the order to fix them in, and the doses that actually work. Written by people who've done this on real pools for 20 years.
9 minUpdated Sep 12, 2026