High TDS at 440 and get to 000

Help,

I have a merlin system with DI, which until now has done great. Water from tap has suddenly gone from 250/270 to as high as 440 (been over 400 for a few weeks) and I can’t get to 000. I’ve changed filters/resin but doesn’t work for very long.

i had been advised to put a carbon filter but that’s 2 (one in merlin)

water from merlin is 35/45 prior to DI and very quickly jump up to 70

I use 250/300 litres per day, usually change resin monthly and filters every 4/6 months and RO membrane only 2 months old

jamesthered said:

Help,

I have a merlin system with DI, which until now has done great. Water from tap has suddenly gone from 250/270 to as high as 440 (been over 400 for a few weeks) and I can’t get to 000. I’ve changed filters/resin but doesn’t work for very long.

i had been advised to put a carbon filter but that’s 2 (one in merlin)

water from merlin is 35/45 prior to DI and very quickly jump up to 70

I use 250/300 litres per day, usually change resin monthly and filters every 4/6 months and RO membrane only 2 months old

Click to expand...

I'm sorry @jamesthered but Merlins aren't good r/o's for window cleaners.

They were primarily designed as under kitchen counter top water purifiers for drinking water in American kitchens. They didn't need to be that efficient.

A fellow window cleaner down the road could only get a 90% tds removal when his Merlin was new. Its worse now.

Merlins come with three housings, the first a fiberdyne sediment carbon filter combo and the other two filters are the membranes. I see Spectrum also supply membranes for them. I'm not sure if they are any better than the original GE membranes though.

The PRF-RO is the replacement for the Merlin but not much better tbh in my opinion.

A water tds of 400 would produce pure at 40ppm. A big di vessel will be needed to polish that off; infact I would probably double di.

If I were in your position I would dump the r/o and go for a better 4021 or 4040 with a good Axeon membrane. Speak to @doug atkinson from Daqua if you need further info.

An Axeon HF5 membrane with 50 psi water pressure removes 97% of my tap water's dissolved solids. If you can achieve similar your pure from the r/o will be around 12ppm.

Thanks very much Spruce,

Ive known for while that as I’ve a mate in Van last couple months that the Merlin is not sufficient but has worked till now. Sadly in a perfect storm of expenses so will limp on for a while. I’ve found another DI vessel and will give that a try.

I had looked at some RO suppliers for advice which has been conflicting at best.

One thing Ive taken from this that I’ve learnt more than when everything works as it should.

Once again thanks for the advice, really appreciated as 12 pints of Speckeled Hen didn’t work