A clear timeline for taking a freshly refilled tub from cold mains water to balanced and sanitised within a day, in the right order.
Every refill is a chance to start fresh. Done in the right order, it takes about 24 hours of background time and maybe 30 minutes of actual hands-on work. Done in the wrong order, it can take a week and use twice the chemicals.
Top up to the marked fill line through the filter housing rather than the open shell. Cover and start the heater.
While it heats, test the fresh water for hardness and alkalinity. These are your starting points. Aim to know what your fill water gives you before you change anything.
Do not add any chemicals at this point. Cold water dissolves things poorly and you risk staining the floor.
Once the water is above 25C, add alkalinity increaser if needed to bring total alkalinity into 80 to 120 ppm. Wait an hour, retest.
Next, address pH. With alkalinity in band, pH is usually stable in the 7.4 to 7.8 range and may not need anything. If it is too high, dose pH down sparingly and wait an hour.
Next, calcium hardness. Top up to 100 to 250 ppm with calcium chloride flakes dissolved in a bucket. Add slowly with jets running.
Once the tub is at temperature (38C), add sanitiser. For chlorine: dose to 5 ppm with granular dichlor. For bromine: load a fresh feeder and dose 30g of sodium bromide to seed the bromide reservoir.
Leave for an hour with the jets on. Test free chlorine or bromine. Adjust if needed.
Finally, dose a non-chlorine shock. Run jets for 15 minutes with the cover off, then cover and walk away.
Next morning, retest everything. The water should be in band on every reading and ready to use.
Cold water does not dissolve granules well, and the readings are not stable until everything has had time to integrate. The phased approach takes longer in clock time but uses less product and gives a far more stable result.
Yes if the rest of the routine has been done well. The shock is belt and braces, oxidising any organic matter the new water picked up from the hose, the filter, or the air. We always include it.