Author Archives: justin

Creature Raid

Over a few days some critters made it into the aquaponics shed roughed things up. First the bagged fish feed was shredded and thrown about, messy eater. The next night our friend chewed through hard plastic containers to get the remaining food. Finally, the beast came bag with indignance to smash some stacks of terracota pots and eat the kale out of the garden beds.

Lesson learned: Critter proof building, be diligent about closing up at night.

Can’t Git (Github) files from my raspberry pi

pi@raspberrypi ~/grownode $ git clone
Cloning into ‘aquaduino’…
The authenticity of host ‘ (’ can’t be established.
RSA key fingerprint is 16:27:ac:a5:76:28:2d:36:63:1b:56:4d:eb:df:a6:48.
Are you sure you want to continue connecting (yes/no)? yesw
Warning: Permanently added ‘,′ (RSA) to the list of known hosts.
Permission denied (publickey).



Need to create a ssh key on the pi for my github user.


 <span class="comment-copy"><code>exec ssh-agent bash</code> then <code>eval ssh-agent -s</code> then <code>ssh-add ~/.ssh/id_rsa</code></span> <pre>

Note – I had to alter ssh key adding step to work

Scrapping Water Heater for Refractory Cement Cast

After a few hours failing to get the electric water heater shell to work as an outer chimney we decided to pick up an 18″ diameter skacrete cast.


Next,  mix up some refractory cement to a cookie dough consistency and fill the void.

Perlite Refractory Cement Mix Recipe:

  • 1.5 parts Portland Cement
  • 2 parts sand
  • 1.5 parts Perlite
  • 2 parts  fireclay

source: Homemade Refractories

6 troughs of slop later:

new critters

Trying 12 red crayfish in the sump / raft tank.  Also got 3 of each snails and Chinese alge eaters for the fish tank.


Function Key / Surface Assist button locking

When using the surface the “Fn” key toggles whether F1-F9 act as function keys or their surface special (mute, devices, settings, etc).  Press “Fn” + “Caps” simultaneously to switch the default action when clicking a F# key.

mystery water loss in system-2

A frozen 1/2 inch of ice around the system had frozen the door shut at the base. Both media beds were somehow still ebbing/flowing when I arrived at the scene but the sump water level was at 1/6th with the rest frozen underfoot.  I can’t figure what failed, likely the string of hard freeze we’ve had in maryland.


When writing a couchdb view you can choose whatever field to emit,  To get a document list in chronological order emit the date field in your view so that a start

View “start_date”

function(doc) {
if(doc.date_start &&


_view/recent_date?startkey=”2015-02-03″ //Get everything after feb 3 2015

_view/recent_date?startkey=”2015-02-01″&endkey=”2015-03-01″ //Month of Feb



Your startkey / endkey request must be formatted the same as dates are stored in your database.  I recommend JSON e.g “2015-01-25 T00:00:00Z”


Inner chimney

The cut section from the water heater needs to be reattached into a cylinder and placed around the brick chimney. It will hold insulation around the vertical brick stack.  Having beat it up to get off of the water heater is making the reattachment difficult.


cannibalized water heater


cumbersome test fit