RO/DI--people who have it can you help me?

[midgetwaiter]

Originally Posted by Myka

The membranes have different efficiency rates.

Filmtec 50 gpd = 98% rejection rate
Filmtec 75 gpd = 98%
Filmtec 100 gpd = 90%
BFS 150 gpd = 98%

If your tap water is 225 ppm, and you're getting 18 ppm out of the RO, then your efficiency is about 92%. If I were you, I would change out your flow restrictor for a 75 gpd, and get a 75 gph membrane that is 98% efficient. This way you should get about 4-5 ppm out of the RO, and your DI resin will last much, much longer. This is probably your cheapest solution.

Myka is absolutely correct. Your unit is working correctly but because of the lower rejection rate of the membrane you are using up DI resin very quickly. This is why the Aquasafe units are cheaper but also not very effective with Alberta water.

The flow restrictor on the Aquasafe isn't a capillary type like used in most systems, it's built into the flush valve so if you do decide to get a new membrane you will also have to replace the restrictor, it costs only a couple dollars.

You will have to decide when you want to swap your DI, it's not a clear cut choice. 6ppm probably isn't a big deal but it depends what that 6ppm is. Test the water for phosphate at least and if you start to see that come through then it's time to replace the DI. Spring is here so you can expect to see some more phosphate then usual.