Hi thanks for all your help i have took out the DI and left it running without that, and it's down to 37 at the moment, so it seems like the DI isn't making any differance,(why would this be?).
I bought this system as it was quite cheap i thought and had the booster pump as well but im on a tight budget i only want enough water to run my backpack for hard to reach windows so im not looking to make loads and loads.