# Low Dilution Rate Chemostat

**URL:** <https://forum.pioreactor.com/t/low-dilution-rate-chemostat/280>\
**Category:** Beginners\
**Tags:** dosing\
**Created:** [April 15, 2024, 9:12pm UTC](https://forum.pioreactor.com/t/low-dilution-rate-chemostat/280 "2024-04-15T21:12:47Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![kradical](https://forum.pioreactor.com/letter_avatar_proxy/v4/letter/k/f19dbf/32.png) [@kradical](https://forum.pioreactor.com/u/kradical)\
**Post date:** [April 15, 2024, 9:12pm UTC](https://forum.pioreactor.com/t/low-dilution-rate-chemostat/280/1 "2024-04-15T21:12:48Z")

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I am trying to run some yeast chemostats at a low dilution rate (0.10hr-1 and 0.05hr-1) and I am having issues getting growth rates matching the dilution rate. Does anyone have any idea why this might be happening or maybe some pointers?

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**Author:** ![CamDavidsonPilon](https://forum.pioreactor.com/user_avatar/forum.pioreactor.com/camdavidsonpilon/32/3_2.png) [@CamDavidsonPilon](https://forum.pioreactor.com/u/CamDavidsonPilon)\
**Post date:** [April 17, 2024, 5:55pm UTC](https://forum.pioreactor.com/t/low-dilution-rate-chemostat/280/2 "2024-04-17T17:55:43Z")

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Hm! We’ve haven’t done a comparison of dilution rate vs growth rate in a chemostat in house. In theory, they should be the same, but that makes a few assumptions including constant dilution. In the Pioreactor, we dilute via discrete drops at specific intervals. That _may_ change the dynamics? I’m not sure myself (_something-something_ differential equations).

I’m curious what other professionals think, too.

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**Author:** ![samunozg](https://forum.pioreactor.com/letter_avatar_proxy/v4/letter/s/e56c9b/32.png) [@samunozg](https://forum.pioreactor.com/u/samunozg)\
**Post date:** [June 1, 2025, 2:45am UTC](https://forum.pioreactor.com/t/low-dilution-rate-chemostat/280/3 "2025-06-01T02:45:15Z")

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Hi Cam,

I think it’d be very useful if you can run the Pioreactor in house in chemostat mode at a few different dilution rates.

We’ve also struggled getting the dilution rate to match the growth rate. Perhaps the growth rate estimation method does not work well with constant dilutions? There’s a report on this forum on a weird growth rate curve in turbidistat mode.

I’m sure you’d be able to provide some valuable insights.

Thanks!