tds-ballpark, my tds#'s, tap#'s, DI#'s

woodstock '69 · 10/06/2006, 07:44 PM

Made and saw my first rodi water today. I have read many comments about the following 3 questions - just re-checking to make sure i'm not missing something.

county treated water reads - 180 tds with the meter that came with airwaterice's typhoon III .

my di water reads 000

are these numbers likely or could the meter be off?

if they are correct, about how many gal will I get out of my di cartridge?

at what tds reading do I replace it?

pressure is at 40psi - is that ok? (can't fix I don't think?)

Michael

AZDesertRat · 10/06/2006, 09:23 PM

Your numbers are probably correct. 180 is a little better than the national average of about 250. 0 indicated TDS is easily attainable with a Typhoon with a new DI cartridge. You really need one more number though to tell how good you are doing and thats the RO only TDS without DI. This number tells you the RO efficiency which is the most critical piece of the filtration system.
As an example I made 15 gallons of RO/DI this evening with my Spectrapure MaxCap RO/DI, my tap water TDS was 847, RO only TDS was 8.1 and RO/DI TDS was 00.1 or less than 0 with a HM Digital COM-100 meter.
That gives me a RO rejection rate of 99.043% which is very very good. A normal Dow Filmtec RO membrane should get you right at 98% so with your tap water TDS of 180 you should be seeing a RO only TDS of about 3 to 5. At that rate your DI cartridge should get you close to 750 gallons per 24 oz DI cartridge refill before you start to see a DI reading of 2 or 3 when you should change resin. Don't let it get past that or you begin to add weakly ionized substances back in to the DI water like phosphates, nitrates and silicates.

AZDesertRat · 10/06/2006, 09:24 PM

Oops, double post!

drummereef · 10/06/2006, 10:47 PM

You are probably right on with the numbers. My municipal water tds is around 350. My RO drinking water stage is 30, and my DI is 0. You should always shoot for 0 tds at the DI stage. Personally I wouldn't put anything with a tds above a 1 in my reef. I notice diatom blooms immediately after I do it.

woodstock '69 · 10/07/2006, 06:32 PM

AZDesertRat - Thanks for the tip. I checked the ro by itself today, (what a nice unit - or do they all have valves for everything?) and it was .002 which seems in-line with the other numbers?

Michael

AZDesertRat · 10/07/2006, 07:26 PM

You should get great life out of the DI resin. I would make it a habit to test the water at least once every 3 or 4 times you use the unit and record the results somewhere so you will have a record of what the beginning readings and date were. This will tell you when to change the pre and carbons (6 months from new), how well the RO membrane is doing, how consistent your tap water is and when to change DI resin (when it starts to read 2 or 3).

clownsntriggers · 10/16/2006, 05:53 PM

My DI water comes out of the Filter at 0.0 and after a few minutes it starts to go up 0.1 and 0.5. I also tested water left in a bucket overnight and it reads 30.... something.

Is this normal and is the water that's been sitting still good?

I am using a Com-100 TDS tester.

clownsntriggers · 10/16/2006, 05:56 PM

Oh, also what setting should I use for the com-100?
There is a bunch of them (some give higher readings).

IT's kind of confusing and the instructions aren't that clear.

hodsgod · 10/16/2006, 06:13 PM

I have 100ppm tds from tap water and 2ppm from my RO unit, I don't have DI.

AZDesertRat · 10/16/2006, 06:13 PM

I use the 442 setting, it seems to be the most accurate for low range testing. When water sets in the DI cartridge it will get down to 0 TDS but once it starts running it may change. If you are on one of the low settings you are still measuring less than 0 TDS with a 0.1 or 0.5. Thats much more sensitive and accurate than any other meter reads!
Water left in a bucket is going to rise as it attracts things from the air and the walls of the bucket.

10/06/2006, 07:44 PM	#1
woodstock '69 Premium Member Join Date: Apr 2005 Location: central virginia Posts: 368	tds-ballpark, my tds#'s, tap#'s, DI#'s Made and saw my first rodi water today. I have read many comments about the following 3 questions - just re-checking to make sure i'm not missing something. county treated water reads - 180 tds with the meter that came with airwaterice's typhoon III . my di water reads 000 are these numbers likely or could the meter be off? if they are correct, about how many gal will I get out of my di cartridge? at what tds reading do I replace it? pressure is at 40psi - is that ok? (can't fix I don't think?) Michael

10/06/2006, 10:47 PM	#4
drummereef Team RC Member Join Date: Jul 2006 Location: STL Posts: 14,754	You are probably right on with the numbers. My municipal water tds is around 350. My RO drinking water stage is 30, and my DI is 0. You should always shoot for 0 tds at the DI stage. Personally I wouldn't put anything with a tds above a 1 in my reef. I notice diatom blooms immediately after I do it. __________________ -Brett 180g Marineland Starfire In-Wall 278 gallon system

10/07/2006, 06:32 PM	#5
woodstock '69 Premium Member Join Date: Apr 2005 Location: central virginia Posts: 368	AZDesertRat - Thanks for the tip. I checked the ro by itself today, (what a nice unit - or do they all have valves for everything?) and it was .002 which seems in-line with the other numbers? Michael Last edited by woodstock '69; 10/07/2006 at 06:43 PM.

10/06/2006, 09:23 PM	#2
AZDesertRat Moved On Join Date: Jan 2002 Location: NW Phoenix Posts: 16,621	Your numbers are probably correct. 180 is a little better than the national average of about 250. 0 indicated TDS is easily attainable with a Typhoon with a new DI cartridge. You really need one more number though to tell how good you are doing and thats the RO only TDS without DI. This number tells you the RO efficiency which is the most critical piece of the filtration system. As an example I made 15 gallons of RO/DI this evening with my Spectrapure MaxCap RO/DI, my tap water TDS was 847, RO only TDS was 8.1 and RO/DI TDS was 00.1 or less than 0 with a HM Digital COM-100 meter. That gives me a RO rejection rate of 99.043% which is very very good. A normal Dow Filmtec RO membrane should get you right at 98% so with your tap water TDS of 180 you should be seeing a RO only TDS of about 3 to 5. At that rate your DI cartridge should get you close to 750 gallons per 24 oz DI cartridge refill before you start to see a DI reading of 2 or 3 when you should change resin. Don't let it get past that or you begin to add weakly ionized substances back in to the DI water like phosphates, nitrates and silicates.

10/06/2006, 09:24 PM	#3
AZDesertRat Moved On Join Date: Jan 2002 Location: NW Phoenix Posts: 16,621	Oops, double post!

10/07/2006, 07:26 PM	#6
AZDesertRat Moved On Join Date: Jan 2002 Location: NW Phoenix Posts: 16,621	You should get great life out of the DI resin. I would make it a habit to test the water at least once every 3 or 4 times you use the unit and record the results somewhere so you will have a record of what the beginning readings and date were. This will tell you when to change the pre and carbons (6 months from new), how well the RO membrane is doing, how consistent your tap water is and when to change DI resin (when it starts to read 2 or 3).

10/16/2006, 05:53 PM	#7
clownsntriggers Registered Member Join Date: Sep 2006 Location: Los Angeles Posts: 66	My DI water comes out of the Filter at 0.0 and after a few minutes it starts to go up 0.1 and 0.5. I also tested water left in a bucket overnight and it reads 30.... something. Is this normal and is the water that's been sitting still good? I am using a Com-100 TDS tester.

10/16/2006, 05:56 PM	#8
clownsntriggers Registered Member Join Date: Sep 2006 Location: Los Angeles Posts: 66	Oh, also what setting should I use for the com-100? There is a bunch of them (some give higher readings). IT's kind of confusing and the instructions aren't that clear.

10/16/2006, 06:13 PM	#9
hodsgod Registered Member Join Date: Jan 2006 Location: Yokohama, Japan Posts: 155	I have 100ppm tds from tap water and 2ppm from my RO unit, I don't have DI.