Pentek prefilter

[Bricklayer]

I've decided to change out my prefilter housing on my RO with a more economical one. Currently I have a big blue 4.5 x 10 filter housing. Filters cost a fortune for them. Around $10.00 each. And are hard to find in bulk in Canada. Even if I get them through a US supplier they are almost $10 each. Compared to the 2.5 x 10" filters that I can get for $1.66 bulk in a box of 50.
My high pressure pump is rated for 6 gpm at 200 psi and 16 gpm at 47 psi.
I don't think I'd ever hit the 16 gpm mark ever because membrane is fed with 1/2" inlets. But I'd like to get the most flow possible.
I noticed most RO's even the larger 600 gph units have the 2.5" x 20" housing. With 3/4" inlet and outlet.
Should I get the same flow with a 2.5" x 10" with 3/4" outlets ?
I've contacted pentek the manufacturer of big blue filters and they can't give me a straight answer
Does anybody use a single 2.5 x 10" filters on their RO's.

[mkoehler79]

I use a single 2 x 10 filter in my RO with a procon 4 GPM pump. My filter is on the high pressure side of the procon though. I've been able to run several hundred gallons of sap through a single filter however I filter the sap going into the feed tank using a milk filter that removes all of the larger particles (pulp, shavings,etc). The filter housing I have has 3/4 npt fittings and is labeled up to 10 GPM capacity. The bulk 50 pack filters I bought are rated 8 GPM.

[Bricklayer]

I got in touch with a tech from pentek. It was interesting explaining to him that I was running maple sap through the filter. But we figured it out.
So to get the same flow as a 4.5 x 10 filter housing I would need 2x 2.5 x 20 filters. Plumbed in parallel. Optimum flow on a brand new filter that's got no restriction on a 4.5 x 10 filter is 20 gpm. Probley more like 15 gpm with cold sap. So as it gets plugged it gets les flow.
Optimum flow on a new 2.5 x 20 filter is 10 gpm. More like 8 or less with cold sap.
All flow rates depend also on the quality of filter used.

Optimum flow on a 2.5 x 10 filter is rated at 10 just like the 2.5 x 20 but filter loses flow faster because of less surface area of the filter.

After all this talking to him about proper flow. I explained to him that the filters only last 1 day with sap and we throw them out daily. And that's the reason I want to change filter housings to a smaller filter. I was able to get a real good price on 4.5 x 10 filters from pentek at around the same price I can buy a 2.5 x 20 filter so I decided to just stay with the bigger filter.

[BAP]

Good information that you got from the tech. It’s nice to have real numbers to use in making a decision.

[mellondome]

What micron of filter are these numbers based on?

[Bricklayer]

I told him we use 5 micron filters. Usually the melt blown foam style filters. So I'm pretty sure thats what he went by.
It's different with every style filter. Which makes sense.