A clear, hour-by-hour routine for getting a tub back to fresh after a busy evening with friends, with the tests that prove you got it right.
A six-bather party leaves more in the water than a fortnight of family use. The right routine the next morning means the tub is ready to use again the same evening. Here is the timeline that has worked for us across hundreds of UK gardens.
Skim any visible debris with a hand net. Hair, plasters, leaves: get them out before the filter does.
Dose a full bottle dose of non-chlorine shock, jets on, cover off.
Take the filter out, give it a thorough hose rinse, and set it aside to drip-dry while the next steps run.
Test free chlorine and total alkalinity. After a party the alkalinity often drops because of CO2 absorption from heavy talking and bathers exhaling.
Top up free chlorine to the upper end of the band (5 ppm) with a small dose of granular sanitiser, jets running.
Replace the filter. Run the jets for 30 minutes more. Cover and leave overnight.
Test free chlorine, combined chlorine, and pH. Free should be at 3 to 5, combined below 0.5, pH between 7.2 and 7.6.
If combined is still above 0.5, dose half a bottle of non-chlorine shock and leave for a couple of hours.
If the water still feels off (smell, foam, slick feel), the load was bigger than the routine could handle. A 25% partial drain and refill puts you back to fresh by the evening.
Same routine, just delayed. Shock, top up sanitiser, rinse the filter, leave for two hours, test. It will catch up by lunchtime.
Yes, to the top of the band (5 ppm) about 30 minutes before they get in. It gives you a buffer for the load they bring with them.