Getting reaquainted with the OA system

Oysters are set to go into pH treatments (ambient, 7.5) on Wedneday 2/8, so on Sunday I went to Manchester to get the OA system running, so we could test the CO2 injectors and Durafets.

  • Steven had opened valves on Saturday, so when I arrived I confirmed that pumps worked, float valves worked, and temperature was 10.3 & 10.4 in the headers, and ~10.8 in the culture tank. This, according to the Durafet’s temperature sensors.
  • Untangled Durafets, and installed one in each header tank, and one in a culture tank.
    • “Pink” in Header 1
    • “Yellow” in Header 2
    • “Green” in culture tank connected to Header 1
    • “Blue” Durafet was malfunctioning; error on control panel showed code “error input pv 1”. Did some user manual research, and a good cleaning might be necessary. Also, Rhonda provided very helpful info on GitHub Issue 467


  • Opened the CO2 valve, and adjusted the regulator to provide for enough/not too much back pressure; setting is currently 50 psi
  • Programmed both Header 1 & Header 2 to maintain pH setpoints of 7.45-7.55; injections are 0.8 seconds in duration, every 100 seconds (if needed)
  • Plugged in algae dosing pumps to see if they work - they do.
  • Identified appropriate tubing for the dosing pumps: 0.250”ID x 0.375”OD x 0.062” Wall Kuri Tec® Series 220 Low Density Food Grade Tubing, Polyethylene, Natural, 500’ Coil Item # 220-0662X500 from Harrington

To Do on Wednesday:

  • Install new valves leading to culture tanks
  • Insulate last 3 tanks
  • Trouble shoot faulty Durafet, as per Rhonda’s suggestions
  • Check continuous data from Durafets in both header tanks to see if pH 7.5 has been maintained. Determine how to adjust settings, if needed.
  • Decide which header tank to use first for CO2 treatment
  • Drain headers, refill (need to do both, so temperatures are the same)
  • Adjust settings on low pH header; it likely has been getting too much CO2
  • Put animals in new tanks
  • Install algae dosing pumps (if not already)
  • Decide if we want to start them on pH treatments that day, or possibly wait until Saturday (if we don’t get the continuous data from Rick, may want to wait…)
  • Review chemistry sampling protocol; Yaamini needs to meet with Safety Dave if she is using HgCl

The OA Wordpress Site is a nice reminder of the OA system troubleshooting and tips learned from past experiments, e.g. my old notebook entries and Hollie’s

Written on February 7, 2017