Hello Ichim,

I've just come across your question and although it's been a while since you asked it, it may still be useful for you to get an answer.

First of all, you are not alone - this is a common question about our reusable tangential flow filtration (TFF) cassettes.

There is no direct answer because it depends very much on the sample properties, which can vary considerably from one application to another. However, effective sample clarification prior to TFF, efficient cleaning of the cassettes after each run, and proper storage (i.e. not allowing the membranes to dry out) between runs are the top three factors to consider for maximizing reusability. On average, we see our customers benefiting from 5-10 uses - which can already provide a strong cost benefit over single use cassettes - and sometimes even more.

A good way to determine when a cassette should be replaced - and you seem to be doing this already, which is great - is to monitor the flux during each run and/or when flushing with water at the end of the cleaning process. In simple terms, this can be determined as the average volume of permeate produced per minute. If you see that the flux is decreasing, we recommend that you replace the cassette.

I hope this helps and please do contact us directly at [email protected] if you have any further questions.

Best wishes,

John