Did you see this by post by Andrew?
Roy,
That's why your resin life is so long. Your system probably removes 98% of the 118 ppm in your tap water, and you're then feeding your resin with product water at only 2 or 3 ppm TDS. If your tap water was, say 400ppm, and you were using a Merlin, you'ld be feeding water at 28 ppm to your resin, and it would only last one tenth as long.
Horses for courses !
Andrew
Got mine from stream tec support was excellent. And the sent all fittings and setup instuctions.
2 x 20" fillter housings
1 x 20" Carbon block fillter
1 x 20" Particulate fillter
1 x 4x40 Pentair R/o
Cost £783.34 this will produce 2000 ltrs 31/2 hrs at 80 psi.
You will not be dissapointed.
Roy