TDS reading

minispider · 07/15/2007, 05:42 PM

Hello everyone, my TDS reading right now is showing between 0.06 tp 0.09 before was 0.00 the water coming in is 145, the unit was installed 04/10/07 and the DI cartridge on 05/07, my question is: which cartridge do I change, the micron cartridge, the carbon cartridge or the DI cartridge. your help will be appreciated

n8rad · 07/15/2007, 05:51 PM

if it was me, i would change the DI first and see what your reading is after that. But thats just my 2 cents.

shag26272 · 07/15/2007, 06:20 PM

I wouldnt change anything , youre even close to 1 yet, some people change it at around 3-5 TDS others 10 TDS

Duff Man · 07/15/2007, 06:45 PM

I agree with Shag, not even at 1 yet. In the future, before changing the DI, check what the RO output is first. If the RO is bad, you will be going through a ton of DI which can be quite expensive.

AZDesertRat · 07/16/2007, 09:11 AM

What kind of TDS meter are you testing with. I am not aware of any hobbyist grade meter that can measure in fractions with the exception of the HM Digital COM-100 and it is only accurate to tenths. I think you may be measuring in the high range or you need to remove the decimals. Its probably reading 6 to 9 TDS and if that is the case you need to replace the DI cartridge.
To troubleshoot the system get a tap water TDS and an RO only TDS and determine what your rejection rate or RO efficiency is. This is an important number that will help you determine how long you can expect your DI to last in the future. Generally you should see a 96 to 98% rejection rate with RO only so tap water TDS of 145 you should be seeing an RO only of 3 to 6 TDS which is better than what your DI is giving you presently. When DI is exhausted it begins to give up what it has filtered out and often in greater quantities than what the original amount was.

wadewood · 07/16/2007, 09:32 AM

at that low levels, I would not change anything. If TDS keeps rising, then change the DI cartridge.

AZDesertRat · 07/16/2007, 12:13 PM

Folks, TDS meters don't register that low. Remove the decimal point.

plummike · 07/16/2007, 01:55 PM

I would clean the meter sensors with DI and change the battery. My system has never discharged less than 003. My inflow in a new housing area with all plastic pipes is ~215 in. The best even with a prefilter before my 3-stage unit is 003 and not for long. I change around 20.

shag26272 · 07/16/2007, 02:17 PM

I figured he had some high end type that measured fractions

minispider · 07/16/2007, 04:58 PM

sorry....now they are 009

AZDesertRat · 07/16/2007, 05:04 PM

Time to change the DI cartridge. Keep an eye on it and try to change it when you start to see a consistent 2 or 3. The problem with DI is once it is exhausted it starts to return the stuff it has filtered out back into the purified water. This can be bad since some of the most weakly ionized substances are phosphates and silicates, both of which you do not want in your tank.

minispider · 07/16/2007, 05:25 PM

Quote:

Originally posted by AZDesertRat
Time to change the DI cartridge. Keep an eye on it and try to change it when you start to see a consistent 2 or 3. The problem with DI is once it is exhausted it starts to return the stuff it has filtered out back into the purified water. This can be bad since some of the most weakly ionized substances are phosphates and silicates, both of which you do not want in your tank.

ummm....I do have another ro/di unit dedicated to my water changes only, I will remove the di cartridge and install it on the aquarium unit and see if the readings change.

07/15/2007, 05:42 PM	#1
minispider Registered Member Join Date: Mar 2007 Location: Pembroke Pines, Fl Posts: 177	TDS reading Hello everyone, my TDS reading right now is showing between 0.06 tp 0.09 before was 0.00 the water coming in is 145, the unit was installed 04/10/07 and the DI cartridge on 05/07, my question is: which cartridge do I change, the micron cartridge, the carbon cartridge or the DI cartridge. your help will be appreciated

07/15/2007, 05:51 PM	#2
n8rad Registered Member Join Date: Apr 2006 Location: Idaho, USA Posts: 374	if it was me, i would change the DI first and see what your reading is after that. But thats just my 2 cents. __________________ Current Tank: DSA NEO 185, Bubble King SM 250, Red Dragon 3 80w, DIY/GEO 612 CaRx, Deltec km500, Gyre 150, (4) Tunze 6105's, (4) AI Hydra 52's 360 gallon Envision in the works

07/15/2007, 06:20 PM	#3
shag26272 Registered Member Join Date: Sep 2001 Location: New Orleans, LA Posts: 3,088	I wouldnt change anything , youre even close to 1 yet, some people change it at around 3-5 TDS others 10 TDS __________________ .

07/16/2007, 02:17 PM	#9
shag26272 Registered Member Join Date: Sep 2001 Location: New Orleans, LA Posts: 3,088	I figured he had some high end type that measured fractions __________________ .

07/15/2007, 06:45 PM	#4
Duff Man Registered Member Join Date: Feb 2007 Location: Chicago's far NW burbs Posts: 629	I agree with Shag, not even at 1 yet. In the future, before changing the DI, check what the RO output is first. If the RO is bad, you will be going through a ton of DI which can be quite expensive.

07/16/2007, 09:11 AM	#5
AZDesertRat Moved On Join Date: Jan 2002 Location: NW Phoenix Posts: 16,621	What kind of TDS meter are you testing with. I am not aware of any hobbyist grade meter that can measure in fractions with the exception of the HM Digital COM-100 and it is only accurate to tenths. I think you may be measuring in the high range or you need to remove the decimals. Its probably reading 6 to 9 TDS and if that is the case you need to replace the DI cartridge. To troubleshoot the system get a tap water TDS and an RO only TDS and determine what your rejection rate or RO efficiency is. This is an important number that will help you determine how long you can expect your DI to last in the future. Generally you should see a 96 to 98% rejection rate with RO only so tap water TDS of 145 you should be seeing an RO only of 3 to 6 TDS which is better than what your DI is giving you presently. When DI is exhausted it begins to give up what it has filtered out and often in greater quantities than what the original amount was.

07/16/2007, 09:32 AM	#6
wadewood Registered Member Join Date: Apr 2002 Posts: 38	at that low levels, I would not change anything. If TDS keeps rising, then change the DI cartridge.

07/16/2007, 12:13 PM	#7
AZDesertRat Moved On Join Date: Jan 2002 Location: NW Phoenix Posts: 16,621	Folks, TDS meters don't register that low. Remove the decimal point.

07/16/2007, 01:55 PM	#8
plummike Registered Member Join Date: Jan 2006 Location: near Pittsburgh Posts: 271	I would clean the meter sensors with DI and change the battery. My system has never discharged less than 003. My inflow in a new housing area with all plastic pipes is ~215 in. The best even with a prefilter before my 3-stage unit is 003 and not for long. I change around 20.

07/16/2007, 04:58 PM	#10
minispider Registered Member Join Date: Mar 2007 Location: Pembroke Pines, Fl Posts: 177	sorry....now they are 009

07/16/2007, 05:04 PM	#11
AZDesertRat Moved On Join Date: Jan 2002 Location: NW Phoenix Posts: 16,621	Time to change the DI cartridge. Keep an eye on it and try to change it when you start to see a consistent 2 or 3. The problem with DI is once it is exhausted it starts to return the stuff it has filtered out back into the purified water. This can be bad since some of the most weakly ionized substances are phosphates and silicates, both of which you do not want in your tank.