Full day at the hatchery working solo; lots accomplished! No major surprises, except for one Pacific oyster mortality in the same tank as last week; it looked like the same oyster that appeared sickly, so while I’m not surprised, 2 morts in one tank is concerning. We will start draining/vortexing weekly, rather than bi-weekly.

Durafet pH look good upon arrival

Sampled for water chemistry, bottles & grab samples taken @ 1:40p. Here’s the setup. You’ll see I’m using Rick’s probe to measure salinity because our probe is not reading out S (but is reading voltage; the built-in temperature probe is thus likely the culprit). I also recorded voltage in micro-siebens/cm (uS/cm), in case I can convert it to S.

Today is a header tank swap day. Here is the plan of attack

• Convert Header 2 from the low pH to the ambient:
  • Turn off inflowing water from large header tank to low pH tank, Header 2
  • Unplug Header 2 pump
  • Turn off CO2 dosing in Header 2
  • Move Durafet probe FROM Header 2 TO Header 1.
  • Begin draining Header 2 (this takes a while, should allow for 30-45 mins mins)
  • Disconnect CO2 line for Header 2’s manchurian injector
• Convert Header 1 from the ambient to the low pH:
  • Close outflow valve on Header 1 to stop flow to culture tanks
  • Connect CO2 line to Header 1’s manchurian injector
  • Keep Header 1’s pump on
  • Turn on CO2 dosing in Header 1
  • Monitor over the next 2 hours to ensure proper dosing.

##### This is how I changed the solenoid settings to stop injecting CO2 into Header 2, & start injecting Header 1. NOTE: the same Durafet is being used (since we only have 3 functioning), so I manually moved the Durafet from Header 2 to 1, as it controls injections.

Video of me changing injection settings

Drained and cleaned all culture tanks. Found 1 Pacific mort in Tan #3: