RODI help. AHH

[AZDesertRat]

Thats not the problem.
A 100 GPD flow restrictor would waste more than a 75 so the waste ratio would be more like 6:1 using the 75 GPD membrane which would result in lower treated TDS, not higher.

Tell us what the exact waste ratio is. Then tell us what the actual temperature and water pressure are. The numbers don't lie.

Make absolutely sure you order a capillary tube flow restrictor you yourself can trim and adjust for your exact and unique water conditions not a fixed restrictor like most vendors pass off on you. The two major vendors that carry capillary tubes are Spectrapure and Buckeye Field Supply and they are $5 or less. Fixed types are a compromise and never quite are accurate, vendors think you are a dummy and can't measure your wate rconditions and trim a piece of spaghetti.

A couple of photos of your RO system and its plumbing would help too, a picture is worth a thousand words. I have been able to troubleshoot hundreds of systems by photos alone.

 

[EVReef3]

I dont have have anything to check my water pressure, what is needed to check that? Anything i can buy locally?

The output water temperature is 60.26 Degree F
The waste produces 550ml of water in 1 minute
The clean produces 50ml of water in 1 minute

I havent permenently placed it anywhere. I am waiting till i resolve the tds issue before placing it somewhere permenent.

 

[AZDesertRat]

You can buy a pressure gauge with a hose bib thread adapter at Lowes or HD for less than $10. Screw it on the wye adapter you have installed on the sink faucet. Why do you have a wye adapter on what I assume is the hot water faucet too? Never use hot water in a RO.

The lines look correct although a little cobbled up. The flow restrictor would either be inside the red waste line or possibly inside the 90 degree elbow it plugs into. Your 550mL to 50 mL is right in line with what you would see with a 100 GPD restrictor on a 75 GPD membrane so you do have a restrictor somewhere. here in Phoenix my TDS is 600 to 850 so in the past I used to run a 100 GPD restrictor to get better flushing of my 75 GPD membrane for longer life and lower TDS. Not all membranes are the same and in most cases you get what you get, this is why I only use the 100% individually hand tested membranes from Spectrapure, they are only $45 for a 90 GPD version and mine is operating at 99.43% removal or rejection rate, a treated TDS of between 2 and 3 with a tap water tDS of 630-650 right now. There is a difference.

 

[EVReef3]

i ran up to HD and got one:


So given that everything else is okay and the membrane is brand new what else can i do?
I dont know how i feel about putting 20TDS water in my reef.
I spent 55$ on the membrane from LFS, and buying another one will still be risking it. I dont know what im doing wrong.
Ordering another unit is something i am thinking about but again, cant be sure if the problem will be solved.

 

[AZDesertRat]

45 psi is at the low end of where a membrane will operate efficiently, 40 psi is about the bare minimum. As a test, monitor your pressure at different times of the day and see if it fluctuates then try making a batch of water when the pressure is highest and see if the TDS drops, it should slightly.

How old is your DI resin? Did you buy it new, from where and was it vacuum sealed when you bought it? Was it still damp or wet when you installed it or was it dry?
Try disconnecting the blue line at the DI canister and make a few gallons of RO only water without the DI and see what the TDS is of that. If it is the same as or less than the RO/DI TDS then you have bad or exhausted DI resin. Another thing you will want to check is that the DI canister is plumbed properly so it fills the cartridge from the outside or bottom up. I suspect it may be incorrect since usually you see the treated DI water exiting the fitting in the front and the line from the RO membrane down to the DI canister is in back out of sight. The bottom up flow ensures all the DI resin comes into contact with water since it has to travel up through the resin, in reverse it can trickle or cascade down with little contact time.

With a tap TDS of 180 and the Osmonics 75 GPD membrane (which unfortunately is actually equal to a Dow Filmtec 50 GPD membrane not a 75 GPD) you shoule be seeing a RO only TDS of between 3 and no higher than maybe 8 TDS. Thats 96-98% rejection. With your low pressure it may be slightly higher but no higher than say 10 TDS worst case if the membrane is functioning correctly.

The GE Osmonics membranes are rated a little different that the industry standard Dow Filmtecs. GE says their 75 GPD membrane will produce 75 GPD at 77 degrees F water temp and 65 psi pressure. A 75 GPD Dow Filmtec is rated at 75 GPD at 77 degrees and only 50 psi or 15 psi less to produce the same water, put 65 psi to the Dow 75 GPD and it produces 100 GPD. Take the GE Osmonics and lower that 65 down to 50 psi and you get only 50 GPD and at 45 psi you will see more like 40-45 GPD tops and that is at 77 degrees F water tempertaure. At 60 degrees F that 45 GPD will now drop to 32 GPD! Your choice of membranes was a snap decision and not the best for your intended use.

You may want to bite the bullet and purchase a Spectrapure 90 GPD Select series treated and hand tested RO membrane at the same exact $45 you already spent and a matched capillary tube flow restrictor you yourself adjust to a 4:1, or in your case with only 180 TDS 3:1 waste ratio and you will get much much better performance guaranteed in writing.

Two things affect the rejection rate or removal efficiency, water temperature and water pressure. Actually there is one more which is the waste ratio, send too much to waste, the transmembrane pressure drops and the efficiency goes down, reduce the waste and the removal goes up but the membrane is not flushed as well so shortens its useful life. The happy medium is 3:1 to 4:1 which is what all manufacturers recommend.

Colder water actually treats better since it is more dense so DO NOT try blending hot and cold or tempering the water to 77 degrees. Leave it cold only. Have you even been in the shower and someone flushes the stool or starts the washer? You get your tush scalded and that is the exact same thing that happens if a membrane is running and they cannot stand anything over 113 degrees F or they are ruined.

More pressure is better, I run my RO/DI at 95-100 psi using a booster pump. My rejection is 99.43% and my membrane is almost 5 years old now and never been serviced or changed. 60 -80 psi is a very good range for pressure and will give you great water quality, 50 is about as low as I recommend and the manufacturers charts and graphs only go down to 40 psi minimum.

Again try making some RO only during your highest pressure period and see what the TDS is. This will tell us a lot.

 

[EVReef3]

I got busy for the past few days but i checked the water directly from the RO and its 19. Same as the water coming out after the DI
So i am thinking the DI cartridge is bad even though i purchased it new.

 

[AZDesertRat]

DI resin has a fairly short shelf life, even if stored properly in a vacuum sealed mylar foil bag and stored in the refrigerator, 6 months maximum if unopened. If it was not good resin to begin with and it was already old or not stored properly it can exhaust in days.

I am very particular about my resins and have tried many over the years before settling on Spectrapure SilicaBuster or todays Super SilicaBuster.