Hot tub water care: the complete guide
The whole picture in one place — the five numbers that matter, their target ranges, how to test, and how to fix each one. The best place to begin, with links to every deep-dive guide.
Read the complete guide →How to read a hot tub test strip
What each pad measures, how to get an accurate reading, and what the numbers should be for a spa.
Read the guide → BasicsStrip says “OK” but the app doesn’t — who’s right?
Why the bottle’s color bands aren’t the ideal spa ranges, and why the hardness pad measures something different.
Read the guide → Fix itHot tub pH too high — what to add and how much
Why spa pH drifts up, what pH decreaser actually is, and how to dose it without overshooting.
Read the guide → Fix itHot tub pH too low — how to raise it safely
Why spa pH drops, what pH increaser actually is, and how to bring it up without overshooting.
Read the guide → Fix itHot tub alkalinity: the number behind your pH problems
Why total alkalinity makes pH bounce around, the 80–100 ppm target, and how to raise or lower it without wrecking pH.
Read the guide → Fix itCalcium hardness in hot tubs: why it matters
What hardness protects, why both low and high cause trouble, and how to adjust it for your fill water.
Read the guide → BasicsHow to shock a hot tub (and when)
What shocking actually does, chlorine vs. non-chlorine shock, how much to add, and how soon you can soak again.
Read the guide → TroubleshootingWhy is my spa water cloudy?
A step-by-step troubleshooting guide, from sanitizer levels to filters — in the order that actually works.
Read the guide → TroubleshootingHot tub foaming: why it happens and how to fix it
Foam almost always traces back to residue, worn-out water, or low sanitizer — not too much chlorine.
Read the guide → TroubleshootingWhy does my hot tub smell?
Chlorine smell, musty funk, or rotten eggs — what each odor means, and why a strong chlorine smell usually means you need more.
Read the guide → MaintenanceHow often should you drain your hot tub?
The simple rule of thumb for drain timing, the signs your water is worn out, and how to refill without a fight.
Read the guide → MaintenanceHow to clean a hot tub filter
When a rinse is enough, when to deep-soak, and the signs it's actually time to replace the cartridge.
Read the guide → MaintenanceHot tub mold and mildew: prevention and removal
Where it grows, why balanced chemistry doesn't stop it, and the difference between preventing it and removing it.
Read the guide → MaintenanceHow to drain and refill a hot tub, step by step
The complete process — the right equipment, the right order, and how to balance the fresh fill.
Read the guide → DecisionsChlorine vs. bromine — which should you use?
An honest comparison of cost, maintenance effort, and feel, and how to switch if you change your mind.
Read the guide → RoutineHow often should you test your hot tub water?
A realistic testing schedule based on how often you soak — plus the moments you should always test.
Read the guide → Inflatable tubsInflatable hot tub water care
Intex, Coleman SaluSpa, Lay‑Z‑Spa — the full routine, and the few things that are genuinely different on a small tub.
Read the guide → BuyingInflatable hot tub buyer's guide
What to know before you buy — inflatable vs. hard-shell, sizing, jets, running costs, and the main brands.
Read the guide → BuyingBest inflatable hot tubs of 2026
Our current top picks by category — best overall, best budget, best for cold climates, and more.
Read the guide → BuyingBest spa chemicals and products for 2026
The short list we'd actually buy, organized by category — plus how often you really need to restock each one.
Read the guide →