I have used Castle Hot tubs for many years for Aqua finesse products. Sarah there Aqua finesse expert is an amazing support when I set up my tub with the Dead Sea experience. The Dead Sea salt experience is amazing product, the water leaves your skin feeling amazing. The combination of Aqua finesse and Dead Sea salt leaves my chemical balance perfect, I don’t have to adjust anything. I live in a hard water area I must also comment that I have had my hot tub running for 12 years. I have only every used Aqua finesse products, my heater recently failed, when the engineer replaced it there was no signs of lime scale in the stainless steel pipe work. Aqua finesse has looked after my hot tub pipe work so well.