What's your TDS?

reefwiser

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So I check my RO/DI output after filling each batch of water in my Brute garbage can to see how my unit is filtering the water. I also check the TDS of my tap water just to make sure the meter is working correctly.
Here are my readings.
93b4286543558419c70bce8f20d2e06f.jpg

ad7f9961bb6531a10c41d1e2c439e99c.jpg


690db167c46c57551e648a8e3760a641.jpg


What is the TDS of your tap water and RO/DI unit?
 

markak

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incoming tap 234 .... after RO membrane 3 .... in storage can 0
 

TheEngineer

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Incoming from well 55-70PPM, after RO membrane 1PPM, after DI 0PPM.
 

AZDesertRat

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You need 3 TDS readings to know how well a RO/DIunit is working. Since the RO membrane does 90-98+% of the treatment this TDS reading is the most important and yet most overlooked. If the membrane is not functioning properly it forces the DI to take up the slack which shortens its life, lowers the treated water quality since DI by itself is not efficient at removing weakly ionized substances and drives the cost of ownership up.

My tap TDS is between 560 and 850 depending on the seasons, source belnds and treatment plants that are in operation, the RO only TDS varies between 2 and 3 and the DI is 0 from both DI cartridges.

You should replace the RO membrane when it is no longer at least say 95-96% rejection rate or removal efficiency which is when the cost of DI resin starts exceeding the cost of a new RO membrane and matched flow restrictor.
 

Opus

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My tap runs between 250 and 450 depending on how low the lake gets and what other water sources they are using. Our main backup water source got shut down because of zebra mussels. Don't know the after RO number but I'm around 5 after the DI. I need to change out the RO filter but just too lazy to do it right now.
 

143MPCo

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hmm...
Tap water...
ImageUploadedByREEF2REEF1443136848.940396.jpg

After DI...
ImageUploadedByREEF2REEF1443136886.335750.jpg
 

143MPCo

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Man that is super low TDS. Come on who can beat 143MPCo. [emoji3][emoji108]
LOL... one of my DI canisters is going on two years, the color changing is just at the bottom but, it still has a 2nd DI it need to deplete and that one's not showing any signs.
 

AZDesertRat

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When you have dual DI you need to monitor the TDS of each canister or cartridge individually. If you are using the same mixed bed resin in both what is normally done is when you first start seeing signs of TDS (tested with a handheld TDS meter, not color changing resins which are very inaccurate and are usually exhausted and passing TDS before you realize it) in the first DI, you move the second DI into the first position since it should not be showing TDS yet, and place a new cartridge in the second position. You get longer DI life that way and better water quality. Even before DI resin is exhausted, indicated either by TDS or color change, it starts releasing weakly ionoized substances such as nitrates, silicates and phosphates. If the first cartridge is relaeasing this to second it too starts exhausting sooner since it is receiving spurts of TDS, usually higher than the tap water since the resin is releasing what has accumulated over time. By monitoring both and keeping both changed as needed you will be better off.
 

Frop

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My RO/DI is new. Here is what I'm getting.
  1. 800 Tap
  2. 670 Water Softener
  3. 80-110 RO @ 65 psi
  4. 0 DI
Some of your guys' tap water is better than my RO.


Now the RO is around 150-170. So... 160/670 24%.. should be 7% apparently. I tried to open the RO canister up to make sure it's sitting fine and it seemed like it was.. :/
 

sundog101

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Now the RO is around 150-170. So... 160/670 24%.. should be 7% apparently. I tried to open the RO canister up to make sure it's sitting fine and it seemed like it was.. :/

How are you measuring tds (or when)? If you measure the water right after you turn it on, the tds is going to shoot up pretty high because of tds creep. When water sits in the ro cartridge it diffuse back across the membrane. Let it run for a few minutes and then see where it's at.
 

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