When to change RODI prefilters

ReefsandGeeks · 10/11/2017, 05:57 AM

Hi All,

I'm coming up on almost a year for my RODI system I installed in my house and am curious to know how to tell when it's time to change out my pre-filters. I have a sediment filter, and (2) carbon blocks prior to the RO membrane. Then I have a tap off of the RO for drinking and a separate line that goes through a DI cartridge for the tank.

I'm not sure how much water I've used in the past year. Because we also use it for drinking water for us and our dog, it's hard to measure how much I use. I can't just say I refill my 55g tanks every so often and estimate total usage.

JustinM · 10/11/2017, 05:58 AM

Do you have a TDS meter?

ReefsandGeeks · 10/11/2017, 06:48 AM

yes, I have the pen style

ReefsandGeeks · 10/11/2017, 06:50 AM

My DI output is still 0, but not sure how to tell if what is going into the RO membrane is too high? I want to make sure I protect the membrane, and ensure that the RO output is working properly for drinking as we use this water to make my new baby's formula as well.

Will RO output increase in TDS after the prefilters are close to exhausted? or is it too late at that point and the RO membrane damaged?

nereefpat · 10/11/2017, 07:17 AM

For this, pressure gauges are more useful than a TDS meter. Feed pressure to the membrane would drop if prefilters are clogged.

Also, the carbon cartridges can be spent. I would change those at least yearly, especially if your source water has Cl, since chlorine can eat the RO membrane.

10/11/2017, 05:57 AM	#1
ReefsandGeeks Registered Member Join Date: Sep 2014 Location: Pittsburgh, PA Posts: 1,708	When to change RODI prefilters Hi All, I'm coming up on almost a year for my RODI system I installed in my house and am curious to know how to tell when it's time to change out my pre-filters. I have a sediment filter, and (2) carbon blocks prior to the RO membrane. Then I have a tap off of the RO for drinking and a separate line that goes through a DI cartridge for the tank. I'm not sure how much water I've used in the past year. Because we also use it for drinking water for us and our dog, it's hard to measure how much I use. I can't just say I refill my 55g tanks every so often and estimate total usage.

10/11/2017, 07:17 AM	#5
nereefpat Registered Member Join Date: Apr 2016 Location: Central Nebraska Posts: 3,190	For this, pressure gauges are more useful than a TDS meter. Feed pressure to the membrane would drop if prefilters are clogged. Also, the carbon cartridges can be spent. I would change those at least yearly, especially if your source water has Cl, since chlorine can eat the RO membrane. __________________ Pat Current Tank Info: 125 in-wall , 40b sump. 6 bulb T5. ASM G2 skimmer. LPS and leathers

10/11/2017, 05:58 AM	#2
JustinM Registered Member Join Date: Nov 2010 Posts: 1,215	Do you have a TDS meter?

10/11/2017, 06:48 AM	#3
ReefsandGeeks Registered Member Join Date: Sep 2014 Location: Pittsburgh, PA Posts: 1,708	yes, I have the pen style

10/11/2017, 06:50 AM	#4
ReefsandGeeks Registered Member Join Date: Sep 2014 Location: Pittsburgh, PA Posts: 1,708	My DI output is still 0, but not sure how to tell if what is going into the RO membrane is too high? I want to make sure I protect the membrane, and ensure that the RO output is working properly for drinking as we use this water to make my new baby's formula as well. Will RO output increase in TDS after the prefilters are close to exhausted? or is it too late at that point and the RO membrane damaged?