Hi experts, so I am finally upgrading to a fancy double boiler (Bye Silvia, thank you for 14 years!) and I want to plumb it in. I have been reading a lot of marketing info about the BWT filters, particularly about the Bestmax premium and was pretty sold on it until I tested my water.

Yesterday I got the API titration test for GH and KH and these were my results for my cold tap water:
GH = 17-18
KH= 7
pH (on a strip)= 7.5-8

Below are some values from the city water quality report for my area:
TDS = 304 ppm
pH = 8.4
Total Hardness (as CaCO3)= 127 ppm
Alkalinity (as CaCO3) = 72 ppm
Chloride = 56 ppm (average)
Calcium = 30 ppm
Magnesium = 14 ppm
Sodium = 56 ppm
Potassium = 2.8 ppm

Will the Bestmax Premium be a good idea? if not which filter will be best?

I will be using this water for the machine and also as the main source of drinking water since I plan to put a tap on it. It goes without sayin that I want to to avoid the scale build inside my new $3k machine.

Thank in advance for all your help, and if you need more information, please let me know.

Oscar

Osanties wrote:Will the Bestmax Premium be a good idea? if not which filter will be best?

If it were me, I would go with RO and a remin filter with this water. That would take care of the chloride, which is a corrosion risk. La Marzocco USA generally recommends RO when chloride ion is above 30 ppm, and Synesso is more conservative about chloride, recommending RO when the chloride ion is above 15 ppm.

Second best would be a conventional softener (sodium or potassium ion exchange). It would drop your hardness to a less scale-prone level and would keep the alkalinity of the incoming water. That alkalinity is a defense against chloride corrosion and you want to keep that.

The BWT bestmax would do a good job making the water less scale prone, but it uses a WAC resin that exchanges H⁺ ions for hardness ions, which lowers the pH and reduces the alkalinity, and you don't want that with this water.

BWT does have a conventional sodium ion exchange softener cartridge (called the bestprotect) but there are lots of options for that that you can get from coffee equipment vendors.

Thank you for your feedback Homeburrero!

Ideally I would go with an RO system but this seems complex for now. Even with my Alkalinity levels at 125 ppm will you be concerned with the pH drop and the chlorides? I was reading somewhere, I don't remember where since I've read way too many things, that WAC with Alkalinity above 100 and Cl- below 80 should be fine.

Again thank you,

Oscar

Osanties wrote:Even with my Alkalinity levels at 125 ppm will you be concerned with the pH drop and the chlorides?

If it is that high on average, I would be less concerned. My advice was based on I thinking you might have an average alkalinity of 72 ppm per the water report. Generally speaking any chlorides may be harmful so there is no clear cutoff. If you have a vintage copper/brass machine then you have reason for more chloride paranoia.

Osanties wrote:I was reading somewhere, I don't remember where since I've read way too many things, that WAC with Alkalinity above 100 and Cl- below 80 should be fine.

That's probably from this Pentair article: /downloads/ ... pdated.pdf which is excellent info from people who know this stuff. It is more permissive than the advice we see from some vendors, and note that it's primarily about stainles steel corrosion. My understanding, mostly from rpavlis posts (Chemistry professor Robert Pavlis, rpavlis was a frequent contributor to HB who had vintage lever machines and shared a wealth of knowledge about physics, chemistry, and water) is that copper/brass is more susceptible to chloride related corrosion than stainless steel.

Update:

So I installed the WBT Filtration system and here are the results of the water coming out on setting 1.

KH: 3 (7 before)
GH: 11 (17 before)
pH: 6-6.5 (having a hard time getting a stable reading, before it was about 8.5)
TDS: 320 (395)

I wish the pH didn't drop so much but i don't know if I can control that. Water taste fine, a little like softened water with a sweeter after taste. Although this could be my mind maybe there is some of the chlorine coming through even thought the carbon in the filter should remove the chlorine.

Aside from that I just got my Lelit Bianca and can't wait to plumb it in in a few weeks!

Osanties

It's not the ChloriNE that tastes sweet, it's the ChloriDE. Chloride slightly improves the palatability of water. With that Bestmax you've removed most of the Alkalinity (buffer) so now the Chloride is the dominant anion in the water and the pH going to be less stable. This is exactly how a WAC cartridge remediates scale, it exchanges some of the Calcium and lowers the pH below the saturation point so the remaining Calcium does not precipitate.

And in regards to the Pentair document provided above regarding WAC cartridges, Chloride concentration, and stainless steel; I believe it should be stated that you can use a WAC cartridge provided the Alkalinity remains above 100ppm POST FILTER.

You should test that water religiously, I would start with weekly testing for pH and Chlorides. Get a cheap pH meter, calibration solution, and a Hach 8-P titration kit.

LA water is notoriously variable. It can be anywhere from just bad to insanely bad for an espresso machine. Likewise, WAC cartridges are best when you are dealing with very stable water. So, now you have a filtration system that requires constant monitoring. It's like maintaining an aquarium.

homeburrero wrote:If it is that high on average, I would be less concerned. My advice was based on I thinking you might have an average alkalinity of 72 ppm per the water report. Generally speaking any chlorides may be harmful so there is no clear cutoff. If you have a vintage copper/brass machine then you have reason for more chloride paranoia.



That's probably from this Pentair article: /downloads/ ... pdated.pdf which is excellent info from people who know this stuff. It is more permissive than the advice we see from some vendors, and note that it's primarily about stainles steel corrosion. My understanding, mostly from rpavlis posts (Chemistry professor Robert Pavlis, rpavlis was a frequent contributor to HB who had vintage lever machines and shared a wealth of knowledge about physics, chemistry, and water) is that copper/brass is more susceptible to chloride related corrosion than stainless steel.

My limited understanding of the difference between Stainless Steel and Copper/Brass as regards Chloride pitting corrosion is that attacks on SS occur at pH levels below 6, and with Copper above pH 8.

Hi Ciaran and Homeburrero

Sorry for he late reply but with the holidays I was a bit occupied. First of all thank you for all your feedback.

So the low pH of the water has been bothering so I went ahead and got a pH meter, calibrated it and measured it. It came out at 5.63 which is way too low for my liking and probably for my new SS boiler.

After seeing this I started playing with the bypass in the BWT filter and moved from setting 1 (10/90) to 2 (25/75) and then to 3 (40/60), flushing the cartridge and taking measurements at at every setting. I settled on bypass setting 3 (40%/60%) and these are the number I am getting out of the filter:

Bypass Setting 3:
pH: 6.3
TDS: 348
GH: 14 (250 ppm)
KH: 3.5 (65 ppm)
Chlorides (56) I am assuming this doesn't change and have not measured it.

Inputting these numbers into La Marzocco water calculator, I went from heavy corrosion on setting 1 to Slightly Corrosive but non scale forming on this setting.

What do you guys think of these numbers are they better? Do I run the risk of scale now?

Thank you again,

Osanties

That setting change didn't make as much difference as I would have expected. (BTW, I was under the impression that, except for the bestmax soft, which runs higher bypass, a setting at 1 is 10-15% bypass and setting at 3 is 30-35% bypass - per post by kolu here. )

Summarizing your GH:KH (as CaCO3) measures

prefilter --- 311:125
postfilter at #3 --- 250:65
postfilter at #1 --- 196:53

Both can be expected to deposit scale, and given the better pH and alkalinity I'd be tempted to go with the harder water at the #3 setting. If it were me, though, I'd be looking into RO + remin, or maybe conventional softening rather than bestmax.

(Geeky details:) A proper LSI would need a calcium hardness number but for a safe WAG we can assume that your calcium hardness is appx 75% of the GH. Then comparing LSI calcs, the harder water would give you a pHs of about 6.2 and the softer one about 6.4 at 125 ℃. The Puckorius pHeq (which may be best to use for LSI comparisons) would be 7.2 for the harder one and 7.1 for the softer one. So taken together maybe 3 tenths of a pH point difference between the two - both would tend to scale and not by much difference.

Thank you, Homeburrero.

I am getting readings all over the place for the alkalinity, I think that since the water sits in the filter the resin keeps decarbonizing so for example on setting 2, I am getting KH = 2 and GH = 11, pH = 6.1- 6.2 initially, and as the filter flushes it goes up. My machine is plumbed in, and the flow through it amounts to about 3 doubles a day and 2 lattes. I flush about 120 ml of water every other day from the steam boiler from the hot water tap, but I am assuming that most of the time it is getting this softened water and not the one that I see after flushing the filter for a bit.

When it comes to the pHeq, is this also assumed for plumed in machines where water does not equilibrate with air? When I measure the pHs of the water out of the coffee boiler and the steam boiler, I am getting pHs in the 6.8s for the coffee boiler and 7.8s for the steam boiler, I am getting that after heating all the CO2 was removed from the water.

It is a bit of a mystery to me what this filter actually does in some of the stages, so I asked BWT about the low pH and they recommended I go to bypass 2, therefore I am there now. Also, when asked about the buffering capacity of the filter this is what their North America rep responded:

"The tap water is entering the filter cartridge . First stage particles are removed
by a pre-filter and substances responsible for bad taste and odor (e.g. chlorine) and particular
organic substances are removed by activated carbon.
After calcium ions (Ca2+) are removed by a weak acid cation exchange resin which is
buffered with magnesium ions (Mg2+). They are exchanged vs. H+ and magnesium ions. The buffering of the resin is done to prevent the decrease of the pH down to pH4.
All calcium ions present in the water are removed. This means that not only limescale is
prevented in the equipment but also calcium sulfate deposits (CaSO4, gypsum).
Finally, the water is treated by activated carbon and particles are removed by in a final
filtration step."

Please keep all the geeky details coming that way I put my chemistry PhD to practice... I don't use it much in this topic since I specialized in another area! I would I love to go to an RO system but my current living conditions do not allow it.

Again thank you!

Osanties