Hot Tub Maintenance Checklist for a Wood Fired Cedar Tub

Hot tub maintenance on a wood fired cedar tub comes down to four things: keep the water in range, keep the firebox clear, keep the cedar and bands checked, and drain and clean on a schedule. None of it takes long, and most of it is a habit rather than a job. Here is the whole routine as a checklist, by how often it comes round, with the additions for an Electric or Hybrid at the end.

Every soak

• Rinse before getting in. Sunscreen, body oils and hair products are what shorten water life. A quick rinse is the single most effective thing on this list.
• Check the water level before lighting. Fill to the line marked on the tub, or at least 4 inches above the chimney collar, and keep it there the whole time the firebox is hot. Never light a fire in a part-filled tub.
• Test if the water is held. Four readings on a strip: alkalinity, pH, calcium hardness, bromine. Test before soaking rather than on a fixed day, since readings move with who has been in.
• Lid on afterward. Floating insulation on the water, lid on top. It keeps heat, keeps debris out, and cuts evaporation.

After every fire: ash and coals

The firebox is the one part of a wood fired tub that asks for attention every time, and it is quick.

1. Let the firebox go cold. Coals hold heat for hours under ash. Do not clear a firebox that was burning the same day.
2. Scoop the ash with the ash scoop that came with the tub, leaving a thin bed on the floor of the firebox; a light layer helps the next fire catch and protects the base.
3. Into a metal container with a lid, never plastic, never a paper bag, never the compost while warm. Set the container on concrete or bare earth away from the tub, the cedar and anything that burns, and leave it there for several days before the ash goes anywhere else. Buried coals reignite; this is how deck fires start.
4. Cold wood ash can go on a garden bed in small amounts, since it is mildly alkaline and adds potassium, or in household waste. Keep it out of the tub water and off the cedar.
5. Do not clear ash into the water, and do not clear it downwind of the tub. Ash in the water raises pH and clouds it.

Between fires, keep the wood dry, split and within reach, and burn only seasoned hardwood. Treated timber, painted wood, pellets, accelerants and fire starter logs damage the firebox and are never used. The best firewood to use covers species and seasoning.

Every two weeks

• Rinse the filter, on any tub that has one. Pull the cartridge, hose it down and refit it. Soak it in The Filter Cleanser only when it no longer rinses clean, or after heavy use. A clogged filter cuts flow through the whole circuit. How to clean a hot tub filter.
• Check the bromine dispenser and set it for the actual pattern of use. A dispenser set for a busy weekend over-doses a quiet fortnight.
• Wipe the waterline. Oils leave a tide mark that lifts easily now and stubbornly later. Soft cloth, mild plant-based cleanser, nothing abrasive, no vinegar.
• Look at the chimney cap. Clear anything caught in the spark arrestor.

Monthly

• Add the stabilizer if the water is held, to keep organic load down so the bromine has less to do.
• Check the cedar bands. Cedar moves with the seasons. If a band has loosened as the boards dried, snug it evenly; do not overtighten. Extra boards came with the tub for when a gap opens.
• Check calcium hardness. It moves slowly, so monthly is enough, and it climbs over time on a tub that is topped up rather than changed.
• Walk round the tub. Drain valve clear, insulation edge intact, nothing leaning on the chimney, firewood stacked clear of the firebox side.

Every three to four months, or at each water change

• Drain and clean. Let the firebox go cold first, and never drain below the fill line while it is warm. Drain fully, wipe the interior with the tub cleanser, rinse, and refill through the hose filter. Draining and refilling covers where the water can go.
• Replace the filter cartridge on a tub with filtration.
• Replace the anodes on an Electric, Hybrid or Wood Fired with filtration: three magnesium anodes, changed every three to four months or once 30 percent or less remains.
• Balance the fresh fill in order: alkalinity 80 to 120 ppm, pH 7.4 to 7.8, calcium hardness 150 to 250 ppm, then bromine 2 to 3 ppm if the water is being held.

On a fresh-fill routine, where the tub is drained after each visit, this whole section happens every time and the two-weekly and monthly items mostly fall away. Fresh fill water care covers that version.

Once a year

• Inspect the firebox and chimney at the start of the season: the chimney sections, the cap, the collar seal, and the firebox lid. Sweep the chimney if creosote has built up, which it will on a diet of wet wood and rarely on dry.
• Decide on the cedar. It silvers if left, which is weathering rather than failure. To keep the original tone, sand lightly and apply a copper-free exterior stain or clear coat to the outside only, never the seats or the firebox fence. Once a year for the lid, every other year for the sides, is what most owners settle into.
• Check the lid and cover. Cedar lid for cracks and hinge play; fabric cover for waterlogging and a dry underside.
• Check the rigid insulation under the tub is intact and the tub is still level.
• Winterize or run through, and make the choice deliberately. Can you use a wood fired hot tub in winter covers both.

If you have an Electric or Hybrid

Everything above applies, and three things are added: a filter rinse every two weeks, the anodes every three to four months, and a look at the equipment in the cedar steps at each water change, where every part is reachable by hand. Set heating and filtration schedules from the touchpad or the Wi-Fi app so filtration runs about 12 hours a day by default, timed around when you soak, and let freeze protection hold the tub through winter for as long as there is power. There is no UV or ozone to service, because none is fitted.

What is not on the list

Servicing the heater, sealing the structure, replacing a liner, or paying anyone to come out. The riveted marine-grade aluminum structure carries a 25 year structural warranty and does not depend on the cedar swelling to hold water, so it can be left empty between visits and through winter. What wears is replaceable and reachable: cedar boards, bands, filter, anodes, and the firebox components. How hard a wood fired hot tub is to maintain is the honest version in prose, and Good Clean Living Water Care covers everything on this list that goes in the water.

Common questions

How much maintenance does a wood fired hot tub need?

Very little, and most of it is habit: rinse before soaking, check the water level before lighting, clear cold ash after each fire, test the water if it is held, and drain and clean every three to four months. A fresh-fill routine, draining after each visit, removes most of the water care entirely.

How do you dispose of hot tub firebox ash?

Let the firebox go cold, scoop the ash into a metal container with a lid, set it on concrete or bare earth away from anything that burns, and leave it several days before it goes anywhere else. Cold wood ash can go on a garden bed in small amounts. Never plastic, never paper, never warm ash in the compost, and never ash into the water.

How often should you change hot tub water?

Every three to four months on a tub with filtration and held water, every week or two on held water without filtration, and after each visit on a fresh-fill routine. Sea water fills are changed every five to seven days.

Do you have to stain a cedar hot tub every year?

No. Cedar silvers if left alone, which is weathering rather than failure. To keep the original tone, most owners do the lid yearly and the sides every other year with a copper-free exterior stain, on the outside only.

What maintenance does an electric cedar hot tub need?

The same water care as a wood fired tub plus a filter rinse every two weeks, a filter cartridge and three anodes every three to four months, and a look at the equipment in the cedar steps at each water change. Heating and filtration run on schedules, and freeze protection holds the tub through winter while there is power.