I recently got a new ro/di unit from brs and after running it awhile noticed I'm getting product water at about 15 ppm. My water pressure is about 35 so I'm not getting the best ro performance. My question is how can I fix this problem? I really don't want to buy a booster pump so would changing the membrane to a high rejection membrane fix my problem? Or how about adding a second di stage?
RO/DI help
- Thread starter Golfman12
- Start date
We need to know what your TDS numbers are:
Out of the tap
After the RO stage
After the DI stage
Adding a different membrane could help, and a second DI stage could also help. However, a booster pump would probably reduce the need for either one and can be found for under $100.
Out of the tap
After the RO stage
After the DI stage
Adding a different membrane could help, and a second DI stage could also help. However, a booster pump would probably reduce the need for either one and can be found for under $100.
Ok, that is 95% RO rejection, that is a little too low. The minimum is 96%, 98% is normal from a good membrane, all the way up to 99%.
Your DI is basically exhausted, used up.
So a couple things, you need to make sure you are getting the proper ratio of waste water to product water from your RO. You need to capture your waste water for 60 seconds and measure it. Then capture your RO product water for 60 seconds and measure it.
There should be 4 times as much waste water as RO water. (100ml vs 25ml as an example).
If this is way off it could be affecting performance. Post here and we can help you adjust the ratio.
Your pressure is low, the least you want is 45PSI and ideally 60+PSI. This has been known to affect rejection rate, but not by more than 1-2% typically.
So you probably need a new RO membrane (especially with such high Tap water TDS) I recommend Spectrapure membranes, they are local and work well. Discount Aquarium on Cave Creek and Peoria is running a special where they are selling Spectrapure items at a discounted price. Or you can drive to Tempe and buy direct from Spectrapure, or you can buy online from Spectrapure. Or BRS, Amazon etz.
Second, you need new DI. You can buy new resin in bulk on ebay/BRS or individual cartridges any of the above mentioned places.
Your DI is basically exhausted, used up.
So a couple things, you need to make sure you are getting the proper ratio of waste water to product water from your RO. You need to capture your waste water for 60 seconds and measure it. Then capture your RO product water for 60 seconds and measure it.
There should be 4 times as much waste water as RO water. (100ml vs 25ml as an example).
If this is way off it could be affecting performance. Post here and we can help you adjust the ratio.
Your pressure is low, the least you want is 45PSI and ideally 60+PSI. This has been known to affect rejection rate, but not by more than 1-2% typically.
So you probably need a new RO membrane (especially with such high Tap water TDS) I recommend Spectrapure membranes, they are local and work well. Discount Aquarium on Cave Creek and Peoria is running a special where they are selling Spectrapure items at a discounted price. Or you can drive to Tempe and buy direct from Spectrapure, or you can buy online from Spectrapure. Or BRS, Amazon etz.
Second, you need new DI. You can buy new resin in bulk on ebay/BRS or individual cartridges any of the above mentioned places.
reefstew
New member
Spectrapure. Buy local
azjohnny
Active member
Aquatec 8800 is a very good pump, when I needed a booster pump it was what I had
http://spectrapure.com/RO-RODI/ADD-...gh-Flow-Pump-Power-Supply-Fittings-and-Tubing
Call Spectrapure and tell them your situation and they will help you out
azjohnny
Active member
I would shorten your flow restrictor and get your ratio to 4/1. We have very poor water quality in the valley and the higher ratio helps to keep the membrane from premature fouling. I also suggest getting a membrane flush which can be used before or after using the membrane
NSimpkins
New member
I got a booster pump and it is amazing. The super high pressure allowed me to also get the 150 gallon upgrade which is just another 75 gpd membrane. Doubles water output and cuts wastewater in half. Can't believe how fast I can make RODI water now. Highly recommend!!! It will pay for its self between your water costs cutting as well as not having to replace filters and membranes so fast.
aguila88psi
Zoa Addict
If the membrane is new it will take a few hours or days of running consistently in order for the membrane to perform properly. They have some sort of protective substance from the factory that needs to be flushed out.
HowManyClowns
New member
I got one after help from many people on this thread. Similar TDS issues. Make sure you flush the hell out of your membrane before making water. Also adding a water softener helped me tremendously. I was getting 35-40tds after the membrane. I am running it pretty fast (above recommended psi) but I am pushing 13tds after membrane and am running my 90gpd system at 132gpd with 4-1 ratio. Also using the spectrapure select membrane
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