RO/DI question

[Treebeard]

I will try to supply a picture when I go home for lunch.
I have the order exactly as you stated below. It is possible that I exhausted the DI resin because I did not change the membrane at the same time I changed the resin and particulate filters, but the guy from Aquasafe said the membrane should last for 12-24 months.

I will also test the raw water and the water after the membrane.
It is a 7 stage filter, if I understand correctly. There are three canister filters, followed by the RO membrane, followed by three DI canisters.
I agree with your comments on this adjustable flow restrictor. It is a real pita to set correctly. What kind of system are you using?

Originally Posted by Myka

What's the TDS of your tap water?

Can you take a picture of your unit (oh that sounds bad!! ), or provide a link to your exact one? As hillegom pointed out, I'm wondering if you have confused the DI cartirdges for particulate and carbon filters. The order should be: particulate, carbon, RO, DI. Once the water passes through the RO it should not be greater than 20ppm or it will exhaust the DI resin very quickly, and will not get it down to 0 ppm TDS. Try disconnecting the hose feed between the RO and the DI and test the water coming out of there (collect it in a clean cup for ease of testing). If it is greater than 20 ppm or approaching 20ppm I would suggest you add a second RO cartridge. This would probably only be a problem if your tap water has really high TDS which is very possible where you live.

EDIT: You have a 7 stage filter system? There is no reason to have a system that large for tap water with a TDS of 50 ppm. My tap water is 90-95 ppm, and my 4 stage (particle, carbon, RO, DI) gets my product water to 0 ppm TDS. I am wondering if your adjustable flow restrictor is faulty...I have never seen one of those before, and I am leary about how it may work.