I'm looking into getting an inline water filter for my espresso machine (and maybe split it off to a faucet for my kettle). I'm in southern California with a high TDS (~215 ppm) and high alkalinity (CaCO_3 around 110 ppm) - pH at 8. My sodium is relatively high 75 ppm.

My primary goal with the water filtering is to prevent the need to descale my equipment. I am budgeting our to afford a higher end machine and I want to have the water quality in place to avoid unnecessary maintenance. I would of course also love the added benefit of better tasting drinks.

The BWT Bestmax Premium seems like a good candidate, but it is also expensive. It feels like I am paying for the advertising... I'm okay paying more for a product if the added benefit is there. Does anyone have any thoughts about the Bestmax and/or other similar products?

Extra thoughts: Ideally, I would do RO and then remineralize. However, I do not have the kitchen real estate to do an RO system. I'm also in an apartment, so no whole-house set up.

Extra question: I don't believe any of these filters will reduce sodium. Should I be concerned for the machine that the sodium is relatively high? Are there prefilters I can use to reduce sodium before using a resin filter?

Edit: I understand there is a fuzzy rule against cross-posting. I acknowledged that I did pose a similar question with less detail to reddit yesterday. I haven't received a response yet, so I am trying here.

Here are a few options for small R.O. systems including one countertop variety.

https://www.amazon.com/APEC-Countertop- ... B06XY66PZJ

https://www.brondell.com/circle-reverse ... on-system/

G.E. also makes a tankless R.O. system that takes up less space called the Merlin reverse osmosis system.

Further you can add an inexpensive inline carbon filter to your cold water side and mix with R.O. water.

murricator wrote:The BWT Bestmax Premium seems like a good candidate, but it is also expensive. It feels like I am paying for the advertising... I'm okay paying more for a product if the added benefit is there. Does anyone have any thoughts about the Bestmax and/or other similar products?
...
I don't believe any of these filters will reduce sodium. Should I be concerned for the machine that the sodium is relatively high? Are there prefilters I can use to reduce sodium before using a resin filter?

Don't worry so much about that sodium. It's higher than the conventional wisdom ideal, but won't harm the machine and is much lower than what a lot of folks on conventional softeners deal with.

You should, however take a close look at your chloride numbers - it can be high in San Diego and likely will go higher as they reduce reliance on purchased water. Chloride can harm the machine, is not reduced by carbon nor by cation exchange resins, and is a primary reason that people resort to RO systems. Some machine manufacturers recommend using RO whenever chloride numbers are above 15 mg/L (Synesso) or above 30 mg/L (La Marzocco). Also, if you do go to an RO system and your tap water's chloride is high relative to alkalinity you will probably want to just choose a remineralization cartridge over trying to blend back minerals from charcoal filtered tapwater.

That bestmax is a decarbonizing filter (aka WAC filter, aka hydrogen ion exchange filter.) There are lots of those available with similar adjustable heads (Mavea Purity C Quell ST, Everpure Claris, etc.) Normally that type of filter would be a reasonable choice at your 110 mg/L level of alkalinity. However, there are caveats about using that type of filter when your chloride is high because they reduce the alkalinity and acidify the water, which exacerbates the problem with chloride. See the guidance here for a technical discussion of that: /downloads/ ... pdated.pdf .

Thank you homeburrero. The last Chloride numbers I have for my water source is around 88.4 ppm (range 61.8 - 110). Given that my pH is already at 8, if the BestMax Premium removes Cl but pushes my pH down, wouldn't that be a good thing? Or is there a concern that the pH can be pushed from 8 to below 7?

murricator wrote:if the BestMax Premium removes Cl but pushes my pH down, wouldn't that be a good thing?

These filters do nothing to reduce the chloride. If you dialed it in to drop to an alkalinity of around 50, it would reduce the pH to maybe below 6.5*, but you'd still have all of that 88 ppm chloride. I think I'd go RO.



* per 2018 SCA Water Quality Handbook, figure 23 on pg 53.

That's disappointing. BWT's site says that it reduces chorine: https://www.bwt-wam.com/en/Products/Pag ... WTGROUP%29 .

I will look into seeing whether I can make an RO system work in my set up. Thank you again for the information I will likely pick up this water guide.

Edit: I realized I liked to Bestmax (non-premium). I don't see the same Chlorine reduction in Premium.

murricator wrote:That's disappointing. BWT's site says that it reduces chorine

Chlorine, yes. Chloride is the same element but is chemically different than chlorine. It is a frequent cause of confusion. Chlorine is typically there in very small amounts, added by the utility for disinfecting the water. It can be easily removed by any carbon block or activated carbon filer, or even by letting the water stand overnight.

I think San Diego uses chloramine to disinfect. A little slower to filter but still can be handled by good carbon filters. Some vendors sell catalytic carbon filters that are supposedly more effective at chloramine removal.

I feel a bit defeated needing to go to an RO system, but I suppose that is what i need to prevent corrosion. I will look into the various options and see if I can make them work in my situation.

Thank you so much for the information!

Hello homeburrero,

I hope you wouldn't mind me asking a follow up Chloride question- you have been so helpful thus far.

If I still decide to go a filter route (i'm leaning against the BWT now) and if I keep my pH near 7 or even above through bypassing/remixing carbon filtered water, would the Chloride still have the acidic impact? I guess the question I am trying to ask, are the high Chloride levels suggesting potential corrosion regardless of pH levels?

My reasoning has bounced back to I think I would feel okay having non-ideal water and still occasionally descaling rather than trying to get an RO system in place. I'd like to invest in a proper RO system when we have a house a few years down the road...

murricator wrote:If I still decide to go a filter route (i'm leaning against the BWT now) and if I keep my pH near 7 or even above through bypassing/remixing carbon filtered water, would the Chloride still have the acidic impact? I guess the question I am trying to ask, are the high Chloride levels suggesting potential corrosion regardless of pH levels?

My understanding is that either low pH or high chloride can cause pitting corrosion and both together make it worse, and especially for brass and copper, chloride is a villain irrespective of pH.


Corrosion is a complex process and I have no real expertise, just rely on what I've read by the late professor Pavlis and others. Consider this post by Dr. Pavlis: Elektra Microcasa a Leva boiler leak problem.

Interestingly I ran across a masters thesis on the dezincification of brass ( https://www.researchgate.net/publicatio ... _Chemistry ) that said that selective dezincification of brass in the presence of chloride was reduced by high alkalinity, but was at its peak at around a pH of 8.

Most of those corrosion studies were at 100 mg/L and higher chloride levels, and you aren't quite there. Using non-ideal water for a while may not cause any real problems. But I don't think I'd risk it on a very valuable or vintage machine. A safe solution to postponing the RO would be to use bottled or made water. A machine that switches between reservoir and plumb-in makes this easy, but there are ways of feeding a plumb-in line from an undersink carboy if you get a machine that doesn't support a reservoir.