Background
Our water has gunk in it (possibly due to this construction). This gunk gets caught in our kitchen faucet’s aerator, and if we don’t clean it out, the water flow will stop completely. Here is what the gunk looks like:

So we decided it was time to install a water filter. The easiest way to filter drinking water is to use a Britta and Pur pitcher, but these don’t work for me. I use them for a bit, and then get tired of changing the expensive replacement filters every month.

The water filter industry has a standard size for under-sink adsorption filters: 9 3/4″. These filters are similar to but much larger than the standard Britta pitcher-style filter, and they only need to be changed every 4-12 months (depending on filter type). You can buy 9 3/4″ filters from several different manufacturers, which helps keep the prices down.

Choosing a Filter

Deciding what kind of filter you need should be easy. In theory, you can call your water utility (or check their website), find out what contaminants are in your water, and then check which filters are certified by the NSF to filter out those contaminants.

I did a bunch of research and found that SF tap water is generally safe to drink. It is disinfected with Chloramine and contains trace amounts of parasites, copper, and lead. The SF PUC monitors Cryptosporidium and Giardia levels every two weeks, and their 2006 Water Quality Report (published 6/07 PDF) shows that all measurable contaminants are below maximum contaminant levels.

Even after finding that SF water is safe for us to drink, I decided to get an activated carbon filter in addition to a sediment filter, because I’m worried that chemicals might enter into the water main during construction, just as visible sediment enters into the water main. Also, I decided that activated carbon was really cool (one gram has a surface area of 500 m² - 1500 m²)!

Choosing a 9 3/4″ Filter Housing

My first thought was to get an OmniFilter OT32 for $140. This unit has a double housing that can fit 2 9 3/4″ filters, and it comes with a string-wound sediment filter and an NSF-certified 0.5-micron enhanced carbon block filter.

After some digging, I found I get a cheaper 2-filter housing from Pentek Filtration. I bought a BFS-201 housing (PDF) from FiltersFast for $57. It’s seems well-built and looks like this:

Installing the Filter Housing

The recommended way of using under-sink filters is to install a second, low-flow-rate faucet to get the maximum effect from your filter. I didn’t want to do this, because I didn’t want to drill a new hole through our granite countertop, so I investigated splicing the filter into our cold water line.

If we only wanted to filter sediment, we could easily add the filter to cold water line, because sediment filters can handle 10 gallons per minute, and our faucet only had a 2gpm flow rate.

Unfortunately, activated carbon filters only work at reduced flow rates. If you only want to filter for what the NSF calls “Aesthetic Effects” (Standard 42), then you can buy a carbon filter that works at 2gpm. But if you want to filter for things like lead, mercury, VOCs, asbestos, MTBEs, Cryptosporidium, and Giardia (what the NSF calls “Health Effects”, or Standard 53), then you have to reduce to the flow rate to 0.5-0.6 gpm.

We decided that it was OK to reduce the flow rate of the cold water at the faucet, since we will still have the full hot water flow rate for washing, and the dishwasher cold supply is already split off. This means we don’t need to drill for a new faucet.

The Pentek filter housing has two 3/8″ female NPT water connections. Our cold water line has a 1/2″ IP straight thread on the faucet side and a 3/8″ compression fitting on the other. To splice the housing into the cold water line, we need to add two 3/8″ NPT to 3/8″ compression adapters to the filter housing, using teflon tape to ensure a good seal:

Choosing a Sediment Filter
Now comes the fun part! We get to choose some filters. Since these are a standard size, we can choose from a bunch of brands, and mix-and-match. Sediment filters are very inexpensive. They are usually made of wound string, last for 10-15,000 gallons, and cost under five bucks. I got the Pentek CW-MF from FiltersFast for $3.30. Looking at the spec sheet, I should have gotten the WP-5 for $5.60, since it has a 5 micron rating instead of a 30 micron rating. It might not matter, since the water will be flowing through a carbon filter anyway. This filter is mostly to lengthen the life of the carbon filter.

Choosing an Activated Carbon Filter
The OmniFilter CB3 seems pretty good. It costs $36 dollars and has NSF Standard 42 and Standard 53 ratings to reduce Asbestos, Atrazine, Cyst, Lead, Lindane, Mercury, and VOCs, as well as Chloramine and Chlorine.

I found Pentek CBR2-10R, which is basically the same thing as the OmniFilter CB3, but it lacks the NSF Standard 53 rating. However, it costs only $17 at FiltersFast, and I decided it was good enough for me. It also has a built-in 0.6gpm flow restrictor, which makes sure you get the full effect of the filter.

After installing everything, this is how it looks:

The water definitely tastes different; it has a slightly-metallic aftertaste, similar to distilled water. I’m interested to see how much stuff the sediment filter catches after 3 months.

Costs
This is my bill from FiltersFast:

Filter Housing BFS0-201 $56.99
Carbon Filter CBR2-10R $16.95
Sediment Filter CW-MF $3.30
Filter wrench SW-1a $2.70
Shipping $1.99
retailmenot.com coupon -$5.00
Total $76.93

I also had to buy two 3/8″ compression to 3/8″ MPT adapaters for $4.79 and a couple hoses from Cole Hardware, bringing the total up to a hundred bucks.

Filed under: food, san francisco | 0 Comments
Tagged: activated carbon , howto , water filter

Today I had to use VNC to debug a remote machine, but firewalls were blocking VNC ports.

After I failed to get my VNC client (Chicken of the VNC) to use a SOCKS proxy, I was able to use SSH port forwarding to get it working. On your local machine type:

This forwards port 5900 on localhost to port 5900 on the remotehost. Then in Chicken of the VNC, open a new connection to localhost. That’s it! EEZ!

It turned out that Xorg was eating all available memory and invoking the oom killer. Sigh.

I guess I could have figured this out without VNC, but I couldn’t reproduce the bug locally, so I watched as a remote user was working on the machine.

Filed under: archive | 0 Comments
Tagged: commandline , howto , ssh , vnc

The greatest thing about Leopard is that you can configure your Mac laptop to backup wirelessly and transparently using Time Machine. You can wander around the world editing files, and your laptop will automatically back them up when you come home and connect to your wireless router, without you having to do anything.

You will need a second Mac or Linux box to host the remote backup. This takes five to ten minutes to set up and configure.

First, configure your remote backup machine. These instructions assume that you are using a Mac for this.

• Configure your remote backup machine with a static IP address
  
  • Your backup machine must be connected to the same wireless router that your laptop will connect to when you are home
  • My wireless router is set to assign IP addresses starting with 192.168.1.100, so I assigned my remote mac to use 192.168.1.23
  • To assign an IP address manually while still using DHCP to get other network settings from your wireless router, go to System Preferences -> Network -> Airport -> Advanced -> TCP/IP and choose “Using DHCP with manual address”
    
• Configure AFP File Sharing under System Preferences -> Sharing
  
  • Select the “File Sharing” checkbox. You should see a message that says “Others can access your computer at afp://192.168.1.23″, or something similar.
  • Click the “+” button under “Shared Folders:”, and add the hard drive you want to store the backups to the list
  • Click the “+” button under “Users:”. Create a user called “backup”. Give this user Read & Write permissions to the backup hard drive
    

• Mount the remote backup hard drive
  
  • In the Finder, choose “Connect to Server…” under the Go menu
  • Type afp://192.168.1.23 in for the server address
  • When asked, log in using user “backup” and type in the password. Be sure to click “Remember password in my Keychain”
    
• Now, Configure Time Machine
  
  • Choose System Preferences -> Time Machine
  • Click “Choose Backup Disk”
  • Choose the remote backup disk that you mounted using AFP
    

If you use your laptop in the standard, Apple-approved manner, then you can configure Time Machine to only backup your Users directory, which will save space and time. Let me know if you need more help!

Filed under: osx, support | 2 Comments
Tagged: backup , howto , Leopard , TimeMachine

To find the size of an image, I usually use ImageMagick’s identify command. Unfortuantely, identify is horribly slow, especially for JPEG 2000 images (thanks to a very slow libjasper).

So instead of using identify:
identify -format "%wx%h" image.jp2

Use exiftool instead:
exiftool -s -s -s -ImageSize image.jp2

exiftool is 62.5 times faster(!!!) than identify for finding image size on my dual 2.0Ghz Athlon.

Filed under: code code | 0 Comments
Tagged: commandline , exiftool , howto , identify , ImageMagick

Our newly-purchased Miele dishwasher was DOA. We had to call the service department, who sent out someone to repair it the same day. When we called, they had us put the dishwasher into service mode, which will tell you which error (”technical fault”) is causing your dishwasher to fail.

These instructions are for a G2140* model Miele Dishwasher

• turn off dishwasher
• hold start
• turn on dishwasher with start button still pressed
• release start button
• press start button 3 times, quickly, holding it in the last time, until the Start/Stop light flashes (no other lights should be flashing)
• Start/Stop should flash for four seconds
• press program button.
• This should cause the rinse LED to flash in a series of long and short blinks. Count the long blinks. Those are the tens digit of the fault. The short blink are the ones digit. For example, ours flashed one long blink and four short blinks, which meant we had a F14 fault.
• You’ll have to figure out what the faults mean. We only know that F14 means “Water intake fault with heater or circulation pump”, or something like that. Our circulation pump was clogged.
• Now, to delete the fault, press and hold the start/stop button for five seconds.

Filed under: support | 1 Comment
Tagged: debugging , dishwasher , howto , Miele , ServiceMode

We finally got a dishwasher! It took some time and work to get it installed, but fortunately we had a lot of help! A couple weeks ago Ken helped remove the old cabinet and Steve wired a new electric outlet. This weekend Paul helped do all the plumbing and install the new cabinet + dishwasher. But when we finally hooked everything up Sunday evening and tried to test it out, the dishwasher flashed a ‘technical fault’ error code. Blah!

Paul called Miele this morning at about 8:45. They did some tests over the phone and said they would have to send a technician out to look at it. After lunch, I got a call Miele saying that they could send someone by in and hour. At 2pm or so, a Miele technician named Glenn shows up, hooks up some debugging equipment, carefully pulls out the dishwasher, unclogs the circulation pump, puts it back together, and it works! Elapsed time from frustrated customer support call to happy customer: about 6 hours! Yay! I think I got lucky because someone had canceled their appointment so they fit me in right way, but still.. yay! So much better than dealing with AppleCare or Blue DoubleCross.

To top it off, Glenn explained a lot about how the Miele worked (I had no idea), and tweeked the software to increase the fill level and water temperature so we can run it on economy mode and still get super-clean dishes. This is like taking your computer to a Linux hacker who hooks you up with a custom distro to get more reliable network connections. Or like taking your car to a gearhead who reprograms the ECU to give you an extra 50HP. Our dishwasher now runs GlennOS. Awesome.

If you care, the clogged circulation pump (error code F14) was suspected to be caused by water drying in the the machine after testing at the factory in Germany. Apparently German water is very hard, and it hadn’t drained completely before shipping (it arrived at our house still full of water), so it left residue in the circ pump.

Here is Zara inspecting the dishwasher (the cabinet work is not done yet):

Here is Paul, who did a weekend’s worth of install work, and the inside of the dishwasher:

This dishwasher connects to the cold water supply, and heats the water depending on what the selected cycle requires. Connecting to the cold instead of hot water supply adds an extra 10-15 minutes to the roughly 2 hour normal cycle, but increases efficiency.

To add a second line to our cold water supply, we replaced the shut-off valve under the sink with a dual 1/2″ to 2 x 3/8″ shut-off valve made by BrassCraft:

If you have 1/2″ unthreaded copper pipe coming into your house, and you need to attach a 1/2″ threaded fitting, you need one of these 5/8″ compression to 1/2″ pipe thread unions. The 5/8″ fits over the unthreaded 1/2″ copper with a compression fitting, and then you can just screw the shut-off valve onto the other side of the union. The fine folk at Cole Hardware helped us find this elusive adapter, shown here covered in teflon tape.

We hope the dish robot likes its new home in our kitchen! Thanks to Ken, Steve, and Paul from helping get it installed, and thanks to Glenn for Miele for making it work!

Filed under: gadgets, support | 2 Comments
Tagged: dishwasher , how to install a dishwasher , howto , Miele , recommended , shag