TDS levels
- Thread starter adamfinke
- Start date
- Tagged users None
Docstomper
Community Member
Did u let it run for about 10 gallons? I found after 10 it drops
I think it is a little high. But it depends on what you start with. If you start with 92 like me then yes it is high. If you are starting with 600 then that is okay. You will just have to change your DI more often.
+1. It is always best to run it for several gallons at a time. Not just one gallon here and there. It will actually make the membrane last longer.
What RODI unit are you using? brand, gallons per day..
adamfinke
Active Member
I have a Culligan water softener and a culligan AC15 no DI. Its only 15gpd more for drinking water I am getting a new system from Spectrapure. I am getting 251 before and 17 after on the TDS.
Trex
Valuable Member
That is giving you about a 93% rejection rate -- which is on the lower side, but would need to know which type of RO membrane you are using to be sure. I use a DOW FilmTec 75 GPD membrane, which gives a 96-98% rejection rate.
To determine how well a RO membrane is working you need a minimum of two TDS measurements, tap water TDS and RO only TDS. For a RO/DI system you need at least 3 including the first two plus the RO/DI or final TDS.
Other things also have an effect on TDS such as water pressure, water temperature, waste ratio and getting more in depth with the tap water TDS figuring the osmotic pressure correction factor.
A 75 GPD Dow Filmtec membrane should give you around 96-98% rejection rate, the 90 GPD Spectrapure will almost always be better than 98% and is guaranteed to be better than 98% with their Select series individually hand tested membranes. This can make a bigg difference since for every 2% you increase the rejection rate you double your DI life. My Spectrapure Select membrane is still at 99.43% rejection after 4 years of heavy use.
I really dislike dual inline type TDS meters and hardly ever recommend them unless its just for a presence/absence or litmus paper type test if you also have a good handheld. I have two of the inlines and a COM-100 handheld and I never even turn the inlines on anymore, they are never correct and just give me a rough idea. A $20-$25 handheld like the HM Digital TDS-3 or TDS-4TM or the new AP=1 are so much more versatile, accurate and they can test anywhere not just two dedicated points.
Other things also have an effect on TDS such as water pressure, water temperature, waste ratio and getting more in depth with the tap water TDS figuring the osmotic pressure correction factor.
A 75 GPD Dow Filmtec membrane should give you around 96-98% rejection rate, the 90 GPD Spectrapure will almost always be better than 98% and is guaranteed to be better than 98% with their Select series individually hand tested membranes. This can make a bigg difference since for every 2% you increase the rejection rate you double your DI life. My Spectrapure Select membrane is still at 99.43% rejection after 4 years of heavy use.
I really dislike dual inline type TDS meters and hardly ever recommend them unless its just for a presence/absence or litmus paper type test if you also have a good handheld. I have two of the inlines and a COM-100 handheld and I never even turn the inlines on anymore, they are never correct and just give me a rough idea. A $20-$25 handheld like the HM Digital TDS-3 or TDS-4TM or the new AP=1 are so much more versatile, accurate and they can test anywhere not just two dedicated points.
Well, it seems to be doing its job well. The water it produces is infinitely better to use in your tank than tap water. Upgrading would be a good idea as well. The one I use is a typhoon III from air water and ice. It has the option to make RO water only and I use that for drinking. It would let you sell the one you have and still make good clean drinking water 
I have the same unit as Loki, and so far have liked mine also. The di bypass is a nice option, I have stopped using the filters for my pur water pitcher and just use the ro unit to fill the pitcher for drinking water and making my coffee in the mornings.
I owned a Typhoon III before selling it to buy a Spectrapure MaxCap, what a difference! The Typhoon could only get it from 800 TDS down to 13-15 TDS with RO only no matter what I did and I even replaced the membrane.
The MaxCap gets the same tap water to between 2 and 3 with RO only so as you an imagine DI lasts much longer, in fact it was 150 gallons per cartridge with the Typhoon and its over 1000 gallons per 20 oz cartridge with the MaxCap. No comparison and the MaxCap even costs less on sale. I thought the Typhoon was the best thing since sliced bread but boy was I wrong.
The MaxCap gets the same tap water to between 2 and 3 with RO only so as you an imagine DI lasts much longer, in fact it was 150 gallons per cartridge with the Typhoon and its over 1000 gallons per 20 oz cartridge with the MaxCap. No comparison and the MaxCap even costs less on sale. I thought the Typhoon was the best thing since sliced bread but boy was I wrong.
Similar threads
