Hot tub advice written for Arizona or Texas does not fit a city where it rains for six months, the water is soft, the trees are big and the power goes out in December. This is the schedule we give owners from Shoreline to Renton.
Weekly
Test alkalinity, pH and sanitizer. Alkalinity first — in Seattle water it is the number that drifts. Rinse the filter with a hose. Look under the cabinet door for a damp patch; a seal that has just started to weep is a cheap repair.
Monthly
Deep-soak the filter overnight and swap in the second cartridge. Check calcium hardness; add increaser if it is under 150 ppm. Lift one corner of the cover — if it is noticeably heavier than last month, it is taking on water.
Every three to four months
Drain with a line flush first, not after. Refill and set the four numbers: calcium 150–250, alkalinity 80–120, pH 7.4–7.6, sanitizer per label. Open the equipment bay with the panels off and let it dry; look for rodent sign, chewed insulation and green on the heater terminals.
September
Before the needles fall: new filter, cover straps checked, cover cleaned and conditioned. Trim the branch that overhangs the tub if there is one — it is the source of half the autumn flow codes in Wallingford and Laurelhurst.
November
Before the storms: surge protector at the disconnect if there is not one, a plan for an outage (cover on, breaker off, call if it runs past two days in a freeze), and a floating thermal blanket if the tub is on a windy lot.
April
After the wet season: dry the cabinet, grease the terminals, check the pump for rust on the shaft, and weigh the cover. This is also the visit where a winter's worth of small problems gets found before summer use makes them big ones.
Questions
Can you do the quarterly drain for me?
Why a second filter cartridge?
Related services
Next note: Why your Seattle hot tub trips the GFCI when it rains