RO/DI System Recommendation

[StirCrazy]

all are pretty much the same and very generic. stay away from calgon ro systems, they are a different design and you have to use there filters.

the ones we use are standard 10X3 filters and down filmtec membrains, the difference between companies come in the accesories they offer, the stickers or paint they put on it or the claims they make.

stay away from anyone claiming to not have any waist.. a dow filmtec membrain is designed to have a reject rate of 4 to 1, so for every gal of good water made you are rejecting 4 gal of water. this ensures the surface of the membrain is properly flushed and kept free of buildup. you can reduce this to 2 to 1 as I used to but then back flushing becomes very important and required more often and for longer periods to flush the membrain. failure to keep the membrain "clean" results in a lower life span.

I would recomend looking for the cheepest set up you can find that has at least three canisters and one RO housing, and a PSI guage (not that important as the companies use garbage ones anyways.. and a backflushing atachment. (although all a back flushing atachment is is a bypass for the flow restrictor so it realy isn't a back flushing per say but a removal of the restriction which allows full flow accross the face of the membrain)

you also want to make sure they advertise they use dow filmtec membrains and not rebranded garbage.. if they say they use there own membrain shop somewhere else.

for sizing you want to figure out you average usage per day and multiply it by 4. I go even bigger but remember they are rated under ideal conditions in a 24 hour period so a 25 gpd membrain will take 5 hours to make 5 gal (aprox) where a 100 gps will make 5 gal in little over and hour. so as a min I would recomend a 100gpd.


Steve

[chewie]

Steve....almost had to buy a new computer monitor as I hit the screen hard trying to squish that bug.....lol....nice

[StirCrazy]

Originally Posted by chewie

Steve....almost had to buy a new computer monitor as I hit the screen hard trying to squish that bug.....lol....nice

nobody has tried that and admidted it for over two years now

Steve

[mike31154]

I'd consider looking at something with a 75 gpd membrane. Production may be a little slower than 100 gpd, but the rejection rate is generally better, so if you plan to add DI stage, that will more than likely last longer. This all depends on your incoming TDS though. RO membrane & DI media are the more expensive components of a water purification system, so you want to maximize the quality there.

[StirCrazy]

Originally Posted by mike31154

I'd consider looking at something with a 75 gpd membrane. Production may be a little slower than 100 gpd, but the rejection rate is generally better, so if you plan to add DI stage, that will more than likely last longer. This all depends on your incoming TDS though. RO membrane & DI media are the more expensive components of a water purification system, so you want to maximize the quality there.

thats true, but I bet if you read the membrain part number from a 100 gpd it will be a 75 membrain. a dow 75 is 75 gpd at 55 PSI.. at 90 PSI, at 65 PSI it is a 100gpd , at 75 its a 120gpd , at 95 its a 150gpd

max PSI is 150 on a DOW 75. so ya you want to make sure you have a real dow 75. what a lot of compaines used to do and I imagin there is a good chance they still do is relable 25's as 50's 50's as 75's or 100's ect...

Steve