Series vs parallel

[Tacotrav]

I am wondering how the membranes are rated when running them series vs parallel.
Will 3 100gpd in series make the system a 300gpd or still only 100?

[DRoseum]

Short answer is still 100 gpd but higher concentrate % than in parallel. I have a blog post in this topic that explains both and hybrid set ups.

https://www.sugartree.run/2020/01/diy-2-stage-portable-hobby-ro.html

[Tacotrav]

So will my pump that’s rated for 100gpd be able to run three 100gpd membranes?

[Clinkis]

The 100 gpd rating is based on how much permeate the membrane should produce in a day. So in theory, 3 membranes should produce 300gpd of permeate. What’s important is keeping the proper flow rate through each membrane which is partly determined by how they are configured (series or parallel). Keep in mind this is based on water not sap. Check what the required flow rate is for the membranes and pick your pump accordingly.