We’ve all spent the last year or more under the shadow of the COVID-19 pandemic, and though some of us may have been vaccinated or come through its various waves it remains far from over. One…

cross-posted from: https://lemmy.ml/post/61845

These are actually quite cool and can serve other purposes. For example they are quite common in aquaculture and are also used in some biological waste water treatment processes.

Commercially available units tent to be quite expensive (>1000€ for a small 5l/min unit).