I think there’s more to membrane life and efficiency than I’ll ever understand. I have a Hydronautics one at the moment that’s been in 6 months and producing at 1ppm. I’ve changed the predictors once and we produce 2,500-3,000 litres a day. Input is 300ppm. I’ve never had a membrane last more than 8 months before and with lower output. Nothing has changed. Same tap, same pump.