[StirCrazy]

Originally Posted by ALBERTA REEF

The way I have build this unit is in the water saver way. The waste water from the first membrane is feeding the second. Both menbrane I am running the 150 gpd flow resrictors. The booster pump is ratted for 100psi. I have a pressure guage on the first menbrane it is at 98-100psi and the second membrane has a guage to it is at 45psi. I have tested it it produces 12.5gph of pure water and my tds meter reads 0. I am really happy way it preforms. Better then that POS Coralife pure flow 2 50gpd when it wants too.

concidering you are in Cow town and you have a high amount of tds in your wagter, I would recomend not doing it that way. what will happen is the second membrain will fail quicker. with only 45psi on the second membrain it should be putting out way under the recomended rating, do you know what kind of membrain it is (brand and modle number) lets say it is a true 150 at 60psi then at 45 you would be lucky if you got 50gpd out of it and under 35 to 38psi you won't get anything. now this is for a tft style membrain which from the housings is what I am gussing you have.

also if you have a 150@ 60psi then by sending 100 PSI to your first you are probably putting out upweards of 250gpd. try disconceting your second membrain and run the one just off 100psi and measure your output. you might be waisting money using a second membrain

the ideal setup is in parralel as then you can feed full psi to both membrains and they will deterorate evenly.

also with flow rates this high you want to run more carbon block filters, especialy if your city uses chlorimene (which most are now) as one filter won't remove it all and Cl is what kills out membrains fast. I upgraded my sediment filter to a 6X10 25 to 1micron absolute graduated filter, then ran 3, 2.5x10 carbon block cartrages, my two membrains then my mixed bed DI, I only had 17ppm water going in and 0 comming out befor the DI, I just did the DI cuz I had it what I also did was instead of running a restrictor I put a needle valve after the two wast water lines joind and I dialed it into a 2.5 to 1 rejection rate. I only went this low as my TDS was so low to start with. for your set up I could see you cutting back to 3 to 1 but I wouldn't go any lower than that as you need the good flow to flush the crap off the face of the membrain so the lower your rejection rate is the faster your membrain will plug and the more important bypass flushing becomes.

Steve