Hot Tub Water Chemistry: A Plain-Language Guide for Alberta Owners

Water chemistry intimidates a lot of new hot tub owners. The good news is that once you understand what each parameter does and why it matters, maintenance becomes routine and takes less than 15 minutes a week.

The Four Core Parameters

There are four numbers you need to track: pH, total alkalinity, calcium hardness, and sanitizer level. Everything else is secondary.

pH (target 7.4 to 7.6): pH measures how acidic or basic your water is on a scale from 0 to 14. At the target range, your sanitizer works efficiently, your shell and jets are protected, and the water is comfortable for your skin and eyes. Below 7.2, water becomes corrosive. Above 7.8, sanitizer loses effectiveness and scale begins to form.

Total Alkalinity (target 80 to 120 ppm): Alkalinity acts as a buffer that prevents your pH from swinging wildly when you add chemicals or when bathers enter the spa. If alkalinity is too low, your pH will be unstable and difficult to control. If it is too high, your pH will be locked high regardless of what you add.

Calcium Hardness (target 150 to 250 ppm): Calcium hardness measures dissolved calcium in your water. Too low, and water becomes corrosive, leaching calcium from your shell, jets, and equipment. Too high, and scale deposits form on surfaces and in plumbing. Alberta's municipal water varies widely: Calgary's water is relatively soft while Edmonton's runs harder.

Sanitizer (Chlorine 1 to 3 ppm, Bromine 3 to 5 ppm): Sanitizer kills bacteria and viruses. Chlorine and bromine are both effective; the choice comes down to personal preference. Bromine is more stable at high temperatures and has a less aggressive odour.

Weekly Maintenance Routine

Test your water with a quality test strip or liquid test kit, then adjust in this order: alkalinity first, then pH, then sanitizer. Adding chemicals in the wrong order makes the process significantly harder.

Shock your spa weekly with a non-chlorine oxidizer to break down organic waste that accumulates from bathers (body oils, lotions, sweat). This keeps your sanitizer working efficiently and prevents cloudy water.

When to Drain and Refill

Total dissolved solids accumulate over time regardless of how well you maintain your water chemistry. A complete drain and refill every 3 to 4 months is standard practice for most Alberta hot tub owners. At the refill, clean your shell, flush your jets, and start with a fresh chemistry baseline.