Quote Originally Posted by Hop Kiln Road View Post
Not sure if I'm passing sugar yet. The sap hydrometer says .4 but the refractometer, zeroed out with evaporation condensate says 0. But I think I'm missing sugar and the ends of the membrane housing are dripping and the drips appear to be increasing. Now the seal on the membrane would be the v-gasket and the brine seal would be the o-rings on the cover ends?
To check for sugar in your permeate boil down some permeate at about a 20:1 ratio. If there is sugar in it it will be easier to measure. I tossed my sap hydrometer because the paper had moved in it and it wasn't accurate. I use distilled water to calibrate my refractometer. The condensate from the steamhood can have sugar in it.

The brine seal is the v groove seal on the outside of the membrane. If it is installed backwards it will let sugar pass and if it is torn it will too. It seems that every RO uses a different membrane housing. Not sure what you have and what is causing the leak.