Small RO pump size question

[GoldyCon]

I'm planning to build a small RO system this fall and was thinking of using 400gpd membranes instead of 150 like all the YouTube videos seem to use unless there is a reason they use the smaller ones that I'm not picking up on. Can I run two 400gpd membranes off the standard aquatech pump 8800?

[GoldyCon]

Also, I have heard that you typically get 1/6th production from the rated gpd so a 400gpd membranes would produce 66gpd. What is that 66? Is it making 66gph of permeate?

[wobbletop]

I don't think the small 400gpd membranes have been available very long, and that's why most people haven't used them. I'm planning to expand my 150gpd membrane with a 400gpd this year.

[hodorskib]

I am planning on doing the same thing this year running 2 400gpd membranes in series using the Aquatech 8800 pump.

[Mark B]

Not only are the 400 gpd membranes a consideration, but you'll also notice the online builds are all plumbed with 1/4" line. My build will be plumbed in 3/8 to help augment the flow. I'm gathering supplies now for the build, but I'm hoping to get to 8% at about 10-12 concentrate gph with three of the membranes.if I get that or better then that in flow I'll be pleased.

[GoldyCon]

Do you think the pump will be able to keep appropriate pressure with a larger line diameter?

[maple flats]

It would keep pressure better with the larger size than the smaller size. Pushing any fluid thru a pipe or tube has line friction. That line friction slows the total flow, the smaller the line the greater that loss. The resistance you want in only in the membrane housing, forcing water thru the membrane. Before and after the membrane you don't want needless line friction loss.

[Clinkis]

Not only are the 400 gpd membranes a consideration, but you'll also notice the online builds are all plumbed with 1/4" line. My build will be plumbed in 3/8 to help augment the flow. I'm gathering supplies now for the build, but I'm hoping to get to 8% at about 10-12 concentrate gph with three of the membranes.if I get that or better then that in flow I'll be pleased.

I think your numbers might be a little optimistic. It's very unlikely you will be able to get to 8% on a single pass which means you will need to do multiple runs or recirculate. As your sugar levels rise your flow rates drop especially at 125psi which is about where the 8800 pumps max out. If you are looking for those types of numbers I would strongly consider going with commercial RO components or at least a larger pump. My RO produces concentrate at 10-12 GPH at around 10% and that is using a 2600 GPD membrane recirculating at 250 psi. Good luck with your build and regardless of what your numbers are it will be a huge time and fuel savings.

[diesels77]

Somebody hurry up and build this!! lol. I was thinking of building one like the original with 6 of the 150 gpd membranes but this has me waiting to see if the 400 gpd membranes is going to be a better solution.

[hodorskib]

already built but won't know until the sap runs how it works!