Sones

Hi I have recently purchased and moved into a new house, great news however, the house has a spa pool which I have had some issues with. The spa is a 5 seater with a capacity of 1200 litres (317 gallons) and has an eco-spa system attached to it (http://www.monarchpoolsystems.com/). The spa is covered when not in use with a hard cover and used by two people for 30min to an hour three to four times a week. Temperature is kept at 37.5 Celsius (99.5 Fahrenheit). The spa is (or was its empty right now for a reason I will shortly explain) a salt water bromine spa. I have used ‘standard pool slat’ and a sanitiser mix from the pool shop (510g/kg chlorine present as sodium dichloroisocyanurate and 150g/kg sodium bromide) these chemicals where left by the previous owner. To set up the spa I originally emptied the spa cleaned the surface with mentholated spirits and dismantled the jets cleaning them in a water and mentholated spirits mix. I then filled the spa and balanced it to the following: Salt: 3700-4300pp Ph: 7.2-7.6 Ta: 80-120 Bromine: 2-6pp For the first few weeks the levels stayed normal then I noticed the that bromine levels increased dramatically, despite removing some of the water (about half on two occasions) the levels have remained dramatically high. I have read a lot of the information on this board and believe that I have a small understand of how the spa chemistry works however I am unsure of the effect of the eco-spa. Any help with the high Bromine levels would be great, is the (510g/kg chlorine present as sodium dichloroisocyanurate and 150g/kg sodium bromide) the right chemical to be using? Should I shock/supershock with bleach? Or should I cut up the spa and bin it to forget the nightmare. Cheers,