Hi,

I tried to search the forums and couldn't find an answer to this, also, the local vendor doesn't have the slightest idea on the reason for 0% bypass.

For either BWT Bestprotect or Brita Purity finest, both SAC (Strong Acid Cation) solutions, the recomended bypass is 0%.
Brita even add a caution statement not to use with and other domestic water-softening systems.


Some info on my setup:
My tap water has 16deg GH and 6deg KH. it changes from time to time, but in general the GH never dropped below 14deg.
Using BWT bestmax premium in the past (WAC solution) I managed to reduce the GH to 9-10deg on 0% baypss. of course scale has built up in the machine. It wasn't too much scale but still more than I wanted for 1 year. Also the low KH and pH were some concern to me and had negative impact on the taste
I recently changed to bestprotect and now I get <1deg GH and 6degKH.

Now, while the GH will drop to minimal after the filter and alkalanity and pH are at the same level and I will avoid scale buildup, I get a very flat and bad after taste when brewing an espresso. It is pretty noticeable that had to I switch to a brita jag filter for now.
I made some GH/KH/PH tests and found out that a very small mixing between tap water (or jag water) and the bestprotect water will give me better brewing water (closer to SCAA specs as a reference but also taste wise), but I wonder if there is any concern to the machine doing so, especially since I can't understand the logic of 0% bypass for SAC or the caution stated on Brita instruction manual.

I would appreciate any insights on this.

wolfm wrote:I tried to search the forums and couldn't find an answer to this, also, the local vendor doesn't have the slightest idea on the reason for 0% bypass.

Since these sofeners don't reduce alkalinity the need to adjust them so as to avoid too-low alkalinity is less. Also with possibly high alkalinity the best way to assure scale-free is to just drop the calcium hardness very low with a zero bypass. That also helps in cases where you may have high sulfate, and calcium and sulfate together can make calcium sulfate (gypsum) scale. I'm only guessing, but I think it may also be possible that these cartridges aren't designed to run bypass water thru a separate carbon filter.

wolfm wrote:Using BWT bestmax premium in the past (WAC solution) I managed to reduce the GH to 9-10deg on 0% baypss. of course scale has built up in the machine.

Thanks for that. Always good to see numbers here, especially for the premium, which seems to have a somewhat capricious behavior. With a 6 °dKH the WAC resin part of the filter would only be expected to drop your hardness by about 6 degrees even on 0% bypass, so that may be as expected. The acidity and the low KH is a valid concern here, so good move on switching to bestprotect.

There is some third hand, and sensible advice from BWT via HB member kolu that you should go the bestprotect when the GH is 6 degrees or more higher than the KH. When the difference between GH (hardness cations) and KH (carbonate anions) is high then you know you have a lot of non-carbonate anions, mostly sulfate and chloride. High sulfate and calcium together may cause calcium sulfate (gypsum) deposits, which aren't removed by typical descaling, so it pays to drop the calcium way low with a conventional softener. And high chloride is a corrosion concern, which is especially bad if your water is acidified and low alkalinity, as with a WAC filter like the bestmax.

In your case, I think it would be good to look into your chloride numbers. If that's high you'll want to consider going to RO treatment. If chloride is OK then I think a conventional (SAC) filter is a good choice. It leaves you with that 6 °dKH alkalinity (107 mg/L CaCO3 equivalent) that some might say would dull the acidity. In brewed coffee, maybe yes, but in espresso you should not taste that.

wolfm wrote:I made some GH/KH/PH tests and found out that a very small mixing between tap water (or jag water) and the bestprotect water will give me better brewing water (closer to SCAA specs as a reference but also taste wise), but I wonder if there is any concern to the machine doing so, especially since I can't understand the logic of 0% bypass for SAC or the caution stated on Brita instruction manual.

If you're adept at mixing valves and plumbing you can do that. You'd want to blend charcoal filtered water with the softened, and plan and test that your final calcium hardness, alkalinity, and sulfate taken together indicate no scale problems. Irrespective of blending you'd still have that high alkalinity.

@homeburrero
Thank you for the answer, much appreciated.

homeburrero wrote:I'm only guessing, but I think it may also be possible that these cartridges aren't designed to run bypass water thru a separate carbon filter.

I can confirm that setting the BWT besthead into any bypass settings does not affect the output of the bestprotect (still <1deg GH no matter what setting I used).


Regarding Sulfate and Chlorides, I don't have any numbers since these are not measured by the water supplier near the homes here, only in the water sources. I will search for a test kit to get a better understanding on the water composition I get, this is very intriguing to me.

I do sense a difference when brewing espresso with lower alkalanity water, maybe not between 4deg to 6deg, but very distinctive between 2deg and 6deg.
Lower KH (and pH) was a lesser concern to me with the bestmax permium since I'm not directly plumbed. I filled the tank in the evening and used it the next day so the KH and pH level went up (tested and verified). In the morning, the Coffee was superb and less tasty in the evening. I moved to bestprotect due to the high GH.
RO is the next option, but will probably comes with a new machine

I moved to 5% mixing ratio for the time being and getting good results in the cup.