Water Care Academy

Too high and it scales. Too low and the water pulls minerals out of the tub itself. The hot tub calcium hardness range, and why both ends matter.

Brown water in a new cedar hot tub is tannins from the wood. Harmless, and it clears in about five water changes. Do not add sanitizer yet.

One page to hand to whoever looks after your tub. What an aluminum hot tub needs, the four numbers, and the short list of products that must never go in it.

Sanitizer is consumed rather than lost, so a zero reading means it has been working. Here is what uses it up, why it stops holding, and what to buy.

Hot tub pH decides whether a soak feels comfortable or leaves skin tight and eyes stinging, and it governs how well your sanitizer works.

Total alkalinity buffers pH, which is why it is corrected first. If your pH will not stay where you put it, alkalinity is almost always the reason.

Hot tub foam is surfactants on the water surface, mostly soap residue, body products and old water. Where it comes from, and how to stop it.

Cloudy hot tub water is suspended particles the filter cannot catch. Usually unbalanced water, a saturated filter, or spent sanitizer.