Replacing RO filters

[rostervandross]

I just bought a secondhand unit made by seachem that is a 4 stage unit that I am trying to refit with new filters.

As I bought it, it was set up and has replacement filters for : Sediment -> Carbon -> Carbon 2 -> Membrane

3 canisters on bottom, membrane on top basically.

So the owner had it set up 10 micron Sediment -> 5 micron Carbon -> 1 micron Carbon. So I did not get a DI cartridge. I plan on buying a DI cartridge.. I have bag of resin but no cartridge. Then it would replace carbon 2?

Q1. While I am ordering a DI cartridge, would you recommend I get a smaller sediment filter than the 10 micron replacements that came with it?

Q2. I also need a new membrane for it. It has a 50gpd dow membrane and I believe a matching 50gpd waste restricting capillary. Buying a 75gpd or 100gpd membrane would just allow me to make more water in a given time correct? Is there any difference to the life or efficiency between them? And if I got a 75 or 100 membrane i would have to get a matching waste line restrictor capillary?



I have a couple other questions to do with modifying it to be able to pull just RO water in addition to being able to make DI water for my reef tank.

Q3. It seems if I were to add a DI cartridge into the third cartridge as it is set up now that all the water must go through the resin before the membrane. In effect making it so I could not pull RO water before the DI stage. So maybe if i bought a separate cannister for the DI and ran the output line from the membrane through it I could pull out either just RO water or then run that RO water through the DI.

Is this sound? Or does the water have to hit DI resin before the RO membrane?




This is what I am thinking may be a better system:

Adding a DI cartridge on the side would allow me to run on the main 3 cartridge body:

Sediment 10 micron -> Sediment 1 micron -> Carbon 1 micron

Which could go to RO membrane, and then optionally into the DI cartridge.

Q5. What do you think of my vision for improving the system?



Thanks!

 

[SubRosa]

1. No
2. Yes, the membrane and restrictor work together to control production.
3. Yes, that is correct. The system is set up for 2 carbon blocks.
4. Yes an add on di canister is the way to go.
5. What you're doing helps improve the quality of the water that goes into your tank.

 

[rostervandross]

Huh so I would actually have to add a separate cartidge for DI since the third chamber is before the membrane?


In other words typically in other systems the water goes to the membrane and then to the DI chamber?


Strange since the system is outlined by Seachem to have a DI stage.. maybe I can reroute the water lines to go from second chamber to membrane back to DI to output.

 

[SubRosa]

You certainly can reroute if necessary. Take a close look. The previous owner could have had it wrong....