Hot Tub Guide

Hot Tub Water Care

Water care sounds intimidating because most beginner guides throw a dozen acronyms at you before explaining anything. It's actually three jobs — balance, sanitation, and oxidation — done on a rotating schedule. Get those three right and everything else follows.

The three jobs

  • Balance keeps the water chemically stable so the sanitizer works and the metal parts don't corrode. This is pH, alkalinity, and calcium hardness.
  • Sanitation kills bacteria and viruses continuously. This is chlorine, bromine, salt (which generates chlorine), or a mineral-plus-sanitizer combo.
  • Oxidation breaks down organic waste (sweat, oils, lotions, cosmetics) that sanitizer alone can't handle. This is weekly shock.

The five numbers to know

  • pH: 7.2–7.8. Below 7.2 the water corrodes metal and irritates skin; above 7.8 it drops sanitizer effectiveness.
  • Total alkalinity: 80–120 ppm. Alkalinity buffers pH — if TA is off, pH swings all over the place.
  • Calcium hardness: 150–250 ppm. Too low and the water eats away at heater elements; too high and you get scale.
  • Sanitizer level: system-dependent. Chlorine 1–3 ppm, bromine 3–5 ppm, salt-generated chlorine per the spa's setting.
  • Cyanuric acid (CYA): 0 for indoor/covered spas, 20–40 for outdoor pools. Spas rarely use CYA because they stay covered.

Salt vs chlorine vs bromine — which one for you

Salt (FreshWater® Salt System). A small amount of salt in the water; the spa converts it to chlorine on demand. Least chemistry handling, up to 12 months between water changes, no chlorine smell. Best for owners who want low-maintenance ownership. Higher upfront cost for the cartridge, offset by fewer water changes and less chemical purchasing.

Chlorine. Cheapest month-to-month. Add granular chlorine 1–3× per week, shock weekly. Requires more attention but well-understood chemistry. Best for owners comfortable with regular water testing and adjustment.

Bromine. Gentler on skin and eyes than chlorine, more stable at spa temperatures. Uses a floating dispenser with tabs. Costs more per gram than chlorine but lasts longer. Best for owners with sensitive skin or who want a consistent low-effort sanitizer.

Minerals + oxidizer. Systems like FROG® use mineral cartridges plus a small amount of chlorine or bromine as backup. Lower chemistry, gentle water, but requires cartridge replacement every 3–4 months.

Weekly water-care routine (10 minutes)

  1. Test all five numbers.
  2. Adjust pH first — it affects everything else.
  3. Adjust alkalinity if it drifted out of range.
  4. Confirm sanitizer level; add more if needed.
  5. Add weekly non-chlorine shock.
  6. Rinse a filter.

Troubleshooting the common problems

  • Cloudy water: usually calcium too high, filter dirty, or oil buildup. Try a clarifier first, then deep-clean filters, then check calcium.
  • Foamy water: almost always body oils, lotions, or detergent from swimwear. Add enzyme cleaner and stop washing swimsuits in regular detergent.
  • Green tint: algae. Rare in spas but happens with low sanitizer + high pH. Shock, brush, rebalance.
  • Chlorine smell: paradoxically means not enough free chlorine. The smell is chloramines (used-up chlorine bonded to organic waste). Shock the spa, wait 24 hours, test again.
  • Skin irritation: usually pH out of range. Test and adjust before adding more sanitizer.

FreshWater® IQ — the shortcut if you have it

Grandee®, Envoy®, Aria®, and a few other Highlife® models come with FreshWater IQ Smart Monitoring. It continuously reads pH, chlorine, and salt levels and pushes maintenance recommendations to your phone. If you own an IQ-equipped spa, follow the app — it accounts for spa temperature, usage, and time-since-last-adjustment better than a manual test schedule.

Water care question?

Bring a water sample to our Mansfield showroom for a free test, or call us at (419) 756-1300. We'd rather answer a chemistry question up front than have you buy the wrong products.

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