I run my hot tub each year and drain / refill every 1-2 months as use dichlor granules and pucks.
However, we have now had water meters fitted and doing this is going to get expensive(!) and so am looking to get a baseload of CYA in the water through granules / pucks and then go to just adding bleach to keep up with the chlorine needs of the water which should allow me to change the water less often.
Standard bleach from stores in the UK is about 1.5% but a local cleaning supplies store has Chlor 5 which is 5% and a gallon is about £3 ($4 USD).
I can't find a list of any other ingredients / perfumes so guessing it will be OK.
Anyone used this or suggest any other alternatives in the UK?