RO/DI filter question

[morty]

I have a Spectraplus 2000 (which Spectrapure doesn't sell anymore) and it has two prefiltering canisters before the RO membrane, and two post-membrane canisters. The last two stages are both DI: the first is their Silicafree anion cartridge, and the second is a dual bed DI cartridge for chloramine removal. I recently learned that my city uses chlorine instead of chloramine, plus the water is heavy in particulates. I also just learned that it's preferable to run softened water thru the filter (which may be a little lower in particulates) so I moved the filter input to soft water.

When the filters need replacement, I'm wondering if I should switch to just one stage of DI after the membrane, using the mixed-bed stuff the Filter Guys sell, and then put the unused DI canister in front of the membrane as another carbon prefilter for better chlorine filtering. So the filter order would go

1u sediment filter --> CTO/2 carbon --> +1 carbon --> membrane --> mixed-bed DI

Or is just one layer of carbon chlorine removal sufficient, and are there better gains for removing other stuff if I switched to the Maxcap dual DI stages which would be

.5u sediment filter --> .5u carbon block --> membrane --> maxcap DI --> silicabuster DI

It seems like I want to get away from what I currently have, which is apparently more designed for chloramine treated water :confused:

[mtfatwork]

Here is how mine is setup:

sediment filter--> Matrix carbon--> RO--> DI--> DI

[sea monkey]

1u sediment filter --> CTO/2 carbon --> +1 carbon --> membrane --> mixed-bed DI



This is the preferred method .

That said, at home i have a kent 5u sediment filter --> .5u carbon block --> membrane --> refillable DI .. This is not ideal but it is what i bought when i started the hobby and I have never had any problems that would cause me to replace it with the preferred solution. I prolly burn through DI and cartridges a bit faster than most I guess.


Just a note, some people don't like 1u sediment filters because they get clogged too fast . if you want the 1u i might consider a depth sediment filter where it starts with a much larger size on the outside but is 1u on the inside . the filter will last much longer because it collects particles throughout the entire filter rather than on just the outside.

[morty]

Here is how mine is setup:

sediment filter--> Matrix carbon--> RO--> DI--> DI

Are you using different DI resins in each canister, or doubling up on the same resin?

[morty]

I prolly burn through DI and cartridges a bit faster than most I guess.

Is this because you think having a second carbon block would save the DI resin more? I thought the carbon blocks were more for preventing chlorine from damaging the RO membrane?

[sea monkey]

yes the second carbon block will save your membrane and DI.

often it is cheaper to replace the carbon blocks than to keep burning through DI.

[sea monkey]

Are you using different DI resins in each canister, or doubling up on the same resin?


My home system just has one refillable cartridge that I fill with a mixed bed DI. I always have zero TDS . IMHO the only real reason to have two cartridges is because your TDS is through the roof or you go through a ton of water and you find yourself having the change the DI cartridges constantly.