Guide topic
Hot Tub Water Care
Plain-English, source-cited guides to keeping spa water clean and balanced.
Guide
Hot tub chemical dosage calculator
How much chlorine, pH up/down, alkalinity and calcium to add for your tub volume and readings — free, interactive.
Read guide →
Guide
Hot tub water balance cheat sheet
Ideal levels for chlorine, bromine, pH, alkalinity, and hardness — and the order to adjust them.
Read guide →
Guide
How much chlorine (or bromine) to add
The per-gallon dosing math, after-soak top-ups, and weekly shock, with a worked example.
Read guide →
Guide
Why is my water cloudy, foamy, or green?
What each symptom means and the order to fix it — including why clear-green and cloudy-green need different cures.
Read guide →
Guide
How to lower (or raise) pH and alkalinity
Which chemical moves which, why alkalinity comes first, and the dosing math with a worked example.
Read guide →
Guide
New hot tub startup: fill and balance
A first-fill, step by step — fill, balance minerals, then sanitize, in the order that keeps water easy.
Read guide →
The app for this
Soak: Hot Tub Assistant
Enter a test reading and your tub volume; Soak gives the exact dose for your products, in the right order, with plain-English guardrails. Pay once, no subscription, no ads, fully offline.