By The Zagosa Team. Published .
Reviewed or updated .
A six-bather party dumps more into the water than a fortnight of family use. Get the next morning right and the tub is ready to use again that same evening. Here is the timeline that has worked for us across hundreds of UK gardens.
Within the first hour
Skim off any visible debris with a hand net. Hair, plasters, leaves: get them out before the filter has to.
Dose a full bottle dose of non-chlorine shock, jets on, cover off.
Pull the filter out, give it a thorough hose rinse, and set it aside to drip-dry while the next steps run.
Two hours on
Test free chlorine and total alkalinity. After a party the alkalinity often dips, thanks to CO2 absorbed from all the talking and breathing.
Top free chlorine up to the top of the band (5 ppm) with a small dose of granular sanitiser, jets running.
Put the filter back. Run the jets another 30 minutes. Cover up and leave it overnight.
The following morning
Test free chlorine, combined chlorine, and pH. Free should sit at 3 to 5, combined below 0.5, pH between 7.2 and 7.6.
If combined is still over 0.5, dose half a bottle of non-chlorine shock and leave it a couple of hours.
If the water still feels off (smell, foam, a slick feel), the load beat the routine. A 25% partial drain and refill has you back to fresh by the evening.
Common questions
What if I forgot to shock and woke up to cloudy water?
Same routine, just delayed. Shock, top up sanitiser, rinse the filter, leave two hours, then test. It will catch up by lunchtime.
Is it worth raising chlorine before guests arrive?
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.