# Pumps not working in chemostat mode

**URL:** <https://www.evolver.bio/t/pumps-not-working-in-chemostat-mode/266>\
**Category:** Software\
**Created:** [February 18, 2021, 12:24am UTC](https://www.evolver.bio/t/pumps-not-working-in-chemostat-mode/266 "2021-02-18T00:24:58Z")\
**Posts on this page:** 1\
**Showing post:** 5

<div class="post-metadata">

**Author:** ![heinsz](https://yyz1.discourse-cdn.com/flex035/user_avatar/www.evolver.bio/heinsz/32/52_2.png) [@heinsz](https://www.evolver.bio/u/heinsz)\
**Post date:** [February 20, 2021, 5:51pm UTC](https://www.evolver.bio/t/pumps-not-working-in-chemostat-mode/266/5 "2021-02-20T17:51:52Z")

</div>

I wouldn’t recommend that for reasons that I won’t go into right now, I can elaborate later if you’re interested. But that would also just be treating the symptom of the underlying problem, which is the error you see in that log.

Try these two things. Increase the `serial_timeout` field in `conf.yml` to 0.7. If that doesn’t work, increase the `time.sleep(0.5)` commands in `evolver_server.py` to 0.7 to 1. My suspicion is that because the command is pretty long its it’s not able to get processed in time before the next commands get sent out of the RPi to the microcontrollers.

---

_[View the full topic](https://www.evolver.bio/t/pumps-not-working-in-chemostat-mode/266)._