Check on heath stack setup

• food still dicey, sometimes the food is unevenly distributed.
  • ordered a new pump head today and they are sending some sample tubing to see if it will solve the problem (see below for more details).
  • animals looked good but some algal floculation
    • counted about 5-7 animals in ~15 mL water/sand grab from second tray in heath stack (“extra” juveniles from variable low pH parents)
      • Pics and footage of animals (variable low pH progeny)
    • need to clean mesh next week
    • need to shuffle trays around

Algal counts

• Matt recommended setters should get a concentration of 100K/mL, but not more than that.

• Inflow algal counts direct from the feeding tube were:
  • H2 (ambient): 4.73 x 10^6 cells/mL
  • H1 (ambient/low pH): 4.8 x 10^6 cells/mL
  • Flow rate of the feeding tube is 10mL/13 seconds = 0.77mL/second = 46.2 mL/minute = 66,528 mL / day = 35,260 M cells/day (66,528mL * 5.3 x 10^5 cells/mL)
    • 35,260M cells get into the header tank each day
• Outflow algal counts were:
  • H2 (ambient): 5.3 x 10^5 cells/mL
  • H1 (ambient): 3.8 x 10^5 cells/mL
  • Flow rate of the outflow is 10mL/3 seconds = 200mL mL/minute = 12,000 mL/hour = 288,000 mL/day
    • 288,000 mL * 5.3 x 10^5 cells/mL = 1.5264 x 10^11 cells/day

• FAO manual recommends 0.4mg dry algae per mg spat per week - 10^6 Iso cells = 0.02mg, so 20M cells/week or 2.857M cells/day

• Setter weight ~= 0.07mm^3 = 0.07mg? - H2 has ~ 52000 animals = 3.640 mg spat - H1 ambient has ~ 60,000 animals = 4.2mg spat

Conclusion

• Ambient should be getting ~ 22.4M cells/day (2.857M cells/day * 7.84 mg total spat)
  • they are seeing 152,640 M cells/day
  • they are getting about ~6800X more than they need (152,640 M / 22.4 M)

Solutions

• will try reducing the diameter of the masterflex tubing
  • Cole-Palmer sending a free 1-ft. sample of skinnier masterflex tubing. It’s about half the diameter of the one currently being used and flows at 1/2 the speed.

• ordered another pump head from Cole-Palmer to eliminate the inconsistent feeding from the “T” splitter that’s currently being used to split the rations between headers

• ordered more 1/4” clear tubing from Amazon to run from the algae header to our headers

Water chem

Kaitlyn and Eileen ran TA on H1 water samples. TA data here and discrete chem data here

• Still need to run poisoned samples from H1T5-T8 from 4/19 and from 5/2. We can do this next week.