[dean smith]

Have been running a merlin ro for about 8 years ,changed membranes about 4 years ago everything fine .tap tds is around the 400 ppm and coming from merlin 8 to 10 ppm on a booster pump .just recently tds rising before di again to around 15 and then up to about 30 and staying at 30 .just replaced prefilter and both membranes now tds after running is 27 and rising to 30 .but  this morning at 7 oclock i tried to run it again and after a few minutes it was down to my favourite no of 8 to 10 so all fine but no after about 2 hours it was back to around 30 to 32 and does not want to come down any lower .any advice please do not want to go for a £ 400 new one yet ..

[EandM]

Are the membranes seated properly ? I've had this before when I've renewed them - one doesn't quite seal properly causing a small amount of high tds water to get past and upset the reading. Try removing and refitting the membranes and checking the TDS again. There supposed to have a satchet of sealer with them too.

[dean smith]

Yes popped them out again about lunch time ,but could not find anything wrong used a little vaseline.really puzzling mw ,ta

[dean smith]

Sorry for this again really could do with some input .today pulled merlin apart and then assembled again put my water softener on a manual regen and waited for it to finish  .started up the merlin and as usual started at about 40 tds and then went down to my normal 8 tds after a couple of mins i was very happy with that so produced about 300 ltrs in 2 1/2 hours  tds gone to 11  but not to worry and now about every couple of minutes its rising i am now at 23 tds and its still rising .has anyone any ideas .could it be anything to do with the softener or has anyone had a softener prob ...