Removing lithium and silicon from RO/DI

KJoFan · Mar 16, 2020

So, I got my most recent ATI ICP results back. My RODI results came back with increased lithium and silicon.

I'm not sure what if anything I can do to remove the lithium but I know that the anion resin removes silicates.

I already am running dual 75 gpd membranes, your typical three stages of sediment/carbon filters and the 3 stage DI setup from BRS with separate anion and cation resins and a mixed bed at the end.

My TDS is 0 but I burn through anion resin like crazy. Anyone know how I could possibly improve this to fully remove silicon? Or is complete removal impossible?

My silicon reading was 117.1 which is exactly 117.1 units higher than it should be.

My source water is essentially hard, iron filled well water that won't be improving or changing anytime soon. I do have a water softener that the water runs through prior to the RO/DI unit.

If I can't resolve this and the overall water quality issues I'm seeing, I will be tearing down. I may be doing that anyway but I thought I'd solicit ideas on this at least.

Val Shebeko · Mar 16, 2020

Aerate your raw ro water before you put through the resin. Makes a bigly difference on resin consumption.

Gareth elliott · Mar 16, 2020

how high is the lithium? Unless its super high probably wont have an effect. Its highly reactive, would check if any of your pumps or fittings are corroded not sure it would make it through a functioning di matrix.

Some well water sources do have very high levels of it. For silicone it can be difficult to remove all of it via a mixed bed, if the source water was very high to start. Fwiw if not having a diatom issue. Its not something i worry about.

KJoFan · Mar 16, 2020

Val Shebeko said:
Aerate your raw ro water before you put through the resin. Makes a bigly difference on resin consumption.

With how my mixing station is setup I don't have the space for another container to aerate first. I know that's always a suggested option. Perhaps if I weren't dealing with 100g at a time I could do it, but at this scale it's not feasible.

Gareth elliott said:
how high is the lithium? Unless its super high probably wont have an effect. Its highly reactive, would check if any of your pumps or fittings are corroded not sure it would make it through a functioning di matrix.

Some well water sources do have very high levels of it. For silicone it can be difficult to remove all of it via a mixed bed, if the source water was very high to start. Fwiw if not having a diatom issue. Its not something i worry about.

Lithium is 3.78. May not be a concern. It's the silicon I'm more concerned about as diatoms are an ongoing issue. Silicon in my display measured at 337.6. Clearly elevated and piling up in there as I continue to add it through top off and new saltwater.

I've done the pump check and all checks out there, other heavy metals are a non factor so I think we're clear there.

My anion canister seems to last forever. I'm wondering if I could/should double up my cation as stages 1 and 2 of the DI and end with a mixed bed to catch the stuff anion is meant to. Aside from that, I don't know what else to try.

Val Shebeko · Mar 16, 2020

Your 100 gal have a lid?

KJoFan · Mar 16, 2020

Val Shebeko said:
Your 100 gal have a lid?

I have two 55g plastic tanks plumbed together. The RO/DI is plumbed to one. I pump the water over to the second one for salt mixing. So, in the end one is saltwater storage, the other fresh water. If that make sense.

KJoFan · Mar 16, 2020

Val Shebeko said:
Your 100 gal have a lid?

Both are lidded.

Val Shebeko · Mar 16, 2020

I use a 50 gal rubber garbage bin, for a lid I use a ceiling light grid, inside a garden pond fountain pump,
Fill it with raw ro water, turn the pump on to stir. Drive the water into the resin with an aquatec booster.
And into another same size bin.
Hey presto, reduces axion consumption by 90 + %