Electrical issues aside, many of the most common spa troubles stem from failures to properly maintain the water’s chemistry.

High temperatures and inconsistent circulation can make a spa an inviting breeding ground for bacteria and algae — but this can be avoided by sticking to a few simple principles.

Test twice a week

In a warm, covered spa, algae blooms can take over in less than a day — and so can bacterial infestations. Thus, although many pools can stay sanitized with a once-a-week chemical checkup, it’s best to test a spa’s chlorine level at least twice a week — and ideally, to encourage homeowners to check the water before each use. It’s better to be safe than sorry.

Take pH in context

Testing the water’s pH immediately after running the spa’s pump and jets will result in a higher-than-usual reading, because the release of carbon dioxide (CO2) from the bubbles drives the water’s pH up. For a more accurate pH reading, wait approximately an hour after the jets have been turned off.

Choose chemicals with care

Some water treatment products can lead to problems that are unique to spa environments — for example, quaternary ammonium (“quat”) algaecides tend to produce lots of foam in bubbly spa water. Just because a product works well in a pool doesn’t necessarily mean it’ll translate to a spa, so check with the distributor or manufacturer before pouring it in.