I live in San Jose, CA with pretty hard water measuring around 430 PPM with a cheap tester (I am waiting on the Hach Hardness Test Kit). I will be receiving my Pro 500 soon and ordered a BWT Filter Pitcher to start but I am thinking that I can use the BWT Bestmax system under my sink to replace and old and never used filter. I can get the 1/4" adapters to go on either end and use the existing 1/4" tubes to swap it in pretty effortlessly. Any reason this might not be a good idea? This has the added benefit that my wife can use the same tap to fill her kettle for her French Press coffee (although hopefully she'll get excited about espresso once I can make reasonable shots/americanos). This is more than I'd like to spend on filtration but I want to avoid the need to descale and making my own water seems difficult to manage in a kitchen that is already tight on space and storage. Thanks!

Actually I don't need the pressure reducer so I can just buy the cartridge, adapters and flex and save some money.

MissingData wrote:I live in San Jose, CA with pretty hard water measuring around 430 PPM with a cheap tester

Ideally you want to know hardness, alkalinity, and chloride before deciding on a treatment method. In the case of San Jose water, it depends on where in San Jose, but most of it is very hard and also has enough chloride to be of concern. Chloride is trouble because it's not removed by conventional filters, including the BWT bestmax filters - generally people go to RO systems when they have a chloride issue.

You can get some numbers from San Jose water utility reports like this: https://www.sjwater.com/sites/default/f ... R-2018.pdf

Note the report indicates that if you are in central San Jose, getting primarily groundwater, your inexpensive TDS meter water would read 230 - 500 ppm (based on conductivity of 470-1000 umho/cm) , and your total hardness would be 150 - 450 mg/L ppm CaCO3 equivalent (8 - 25 German degrees). But the chloride ion would be in the 20 - 90 ppm range, averaging 56 ppm. That would be enough to make me consider using RO treatment. (La Marzocco recommends RO when the chloride is above 30 ppm, Synesso recommends when above 15 ppm.) Chloride is especially corrosive to brass and copper, so would be of special concern for a valuable vintage machine that has irreplaceable brass or copper components.

Wow thanks - I looked at that report before but didn't really know what to focus on besides hardness, calcium etc. This is concerning and I'm frustrated by how bad our water is. I suppose I will look for a remineralizing RO system instead of the Bestmax. Any suggestions? Or would there be a compelling reason to put them in series?

MissingData wrote:I suppose I will look for a remineralizing RO system instead of the Bestmax. Any suggestions?

I've never purchased an RO system and don't know much beyond what I see on this forum. For inexpensive systems that use a remineralizer it seems like the Apec, Home Master, and iSpring undersink systems that you can get from Amazon, Home Depot or Costco are somewhat popular. See Reverse osmosis water system recommendation.

A common complaint of remineralizers, especially the ones designed for the 'alkaline water' market give you a lot of mineral and high pH when the system has been idle a long time, but very little once the water has been flowing. Some remin cartridges advise that you give them a purge if the water use has been idle overnight.

if you have water is really high in chloride but not so high in hardness and alkalinity, blending is not advisable. But your water has a high enough hardness to chloride ratio that you could use a blending system. Of the HB sponsors that sell filtration equipment, I only see one (Prima) that sells an RO system, and they sell the Optipure systems that do allow blending. But that's a high-end system - even the small versions cost $2000 or more.

Some HB members have reported plumbing up their own bypass/blending valve system. I noticed one relatively inexpensive RO with blending system here: https://www.craftbrewwater.com/products ... 6636411201. But know nothing about it and have seen no reports or opinions about it in espresso forums.

MissingData wrote:Or would there be a compelling reason to put them in series?

Putting a Bestmax in series with an RO system would be a waste of money. There are cases where the water is so very hard that the RO system's specs require that you soften it before it goes into the RO, but you would not use a bestmax for that.

Thanks I will look into your suggestions. As for the series question, I meant mains -> RO -> Bestmax as a way to remineralize the RO output.

MissingData wrote:As for the series question, I meant mains -> RO -> Bestmax as a way to remineralize the RO output.

The bestmax would do nothing for you there. But BWT has a cartridge called a Bestmin that is designed for that purpose. BWT Bestmin for remineralization

Ok thanks - I clearly have a lot to learn and am frankly overwhelmed by this. Tried to get more detailed information from my water utility but they don't answer the phone. I'll keep trying to reach them and learn more about this and plan on using bottled water when my machine arrives until I arrive at a solution. Really appreciate your help.

Oh and I just tested my water with the Hach 5B test - it took 32 drops to get to blue (turned purple after 31). I will retest a few more times but this water is hard.

I have a whole house water softener with a bypass for the kitchen sink (cold) tap. These are my findings: