Baseline OD readings change after rotating vial with vial aligner

I’m finding that the baseline OD reading changes after rotating the vial 90 degrees.
I think this is because the vial aligner is asymmetric, resulting in a vial that is not centered in the smart sleeve. This could result in more air between the photodiode and the glass vial.
Check out the image below. I found similar phenomena on all 16 vials after rotating them.

Thanks for noting that.

The vial aligners are for keeping the vials in place after the experiment is started. The normalization during the beginning of the experiment should help out with the offset. I would not recommend rotating the vials during the experiment.


Is there anything wrong with using tape instead of the 3D printed vial aligner? As in just taping around the circumference of the upper vial section twice? This would keep the vial centered. Also, the 3D printed parts break frequently.

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eVOLVER is meant to be a flexible platform to use and redesign for your own experimental needs. So do whatever makes the most sense for your experiments. Whatever works best for us, might not work best for others! It is encouraged to share whatever ideas, hacks, and best practices to the community but there is no right or wrong way to operate the machine.