RO Help

[cfmx]

Ok so what am I doing wrong??!!
We have a 5 stage RO/DI unit that seems to do a great job but for a very little period of time.
For instance about 2 months ago we just replaced all filters including the membrane our water was testing out at 0 after a couple of uses it steadly increases.
Today I checked the and the ppm 32. I changed out 10 micron, 5 micron sediment filter, 1 micron carbon filter and back flushed the membrane unit. Then ran it for a little bit and rechecked the ppm (1). After making 40 gallons of water the ppm is now 6.
I checked our tap water which reads at 238 ppm.
What is wrong.