R/O Machine

Kkubiak · 04/14/2006, 12:50 PM

How do you know when it is time to change the filters on the R/o machine. I have a kent marine but I am not sure what model. It has two chambers underneath and a top tube which I think is the deionizing chamber. It has probably been 6 years since I used it to make salt water. Do you ever need to change the top canister or just the bottom two. Also is it a good brand to use in a reef aquarium.

kau_cinta_ku · 04/14/2006, 01:18 PM

is it an ro unit or rodi unit? the 2 canisters on the bottom are your sediment and carbon cartridges and the top i am guessing is the membrane if it has been 6 years i would change all the filters. the carbon and sediment need to be changed every 6 monthes regardless and the membrane about every 2 years

smleee · 04/14/2006, 01:24 PM

Yes the prefilters need to be changed every 6 months regardless. The membrane needs to be changed when the rejection ratio (you need a TDS meter for this) falls below a certain range compared to a new membrane, this varies with the make of membrane. For instance, if you have a 75GPD Dow FilmTec membrane the rejection ratio is 98%; when you drop to about 90% you want to change it. As said you should replace the membrane, without proper storage care the membrane is not good to use anymore. Do you think you can post a pic of it or maybe one that looks like yours?

eee

Kkubiak · 04/14/2006, 01:38 PM

i think I will do like you say and replace them all. i tried to download pictures but they are to big, too many kb's.

smleee · 04/14/2006, 02:00 PM

What GPD is your unit? I would replace the membrane with a 75GPD Dow FilmTec membrane, these are the best performing membranes available. Depending on your current membrane you may have to change the flow restrictor.

eee

bertoni · 04/14/2006, 02:52 PM

I use a TDS meter to monitor the quality of the water from my RO-DI unit. That's a reasonable way to know how it's doing.

Kkubiak · 04/14/2006, 04:57 PM

Where can I find the Dow Film Tec and how do I change out the flow restrictor? It looks as if it is just a part but wherre would I find one? Also how does a TDS meter work and what does it tell me? Thanks for the help guys.

kau_cinta_ku · 04/14/2006, 05:56 PM

go here and post a thread to Bryan he can set you up with all the filters and membrane stuff you need

http://www.reefcentral.com/forums/fo...s=&forumid=420

bertoni · 04/14/2006, 06:02 PM

http://www.reefkeeping.com/issues/20...ture/index.php

That articles talks about TDS. The TDS meters we use measure conductivity, which is an indication of the number of charged ions in the water.

smleee · 04/14/2006, 11:13 PM

Quote:

Originally posted by Kkubiak
Also how does a TDS meter work and what does it tell me?

The TDS meter is essential for telling you how well your RO/DI unit is working. For instance, if your incoming water to the RO/DI unit is 100 ppm, with a 75GPD Dow FilmTec membrane you should get about 2 ppm after the water goes through the membrane (98% rejection ratio). After going through the DI (if you have it) it should be 0 ppm. The TDS meter will tell you when to replace the DI or membrane and also help you "debug" the system if you are not getting expected results. But you should always check your water when you make it.

eee

purelyh2o · 04/15/2006, 12:04 AM

6 years..wow

Time to change the rubber on the car...

After 6 years I would definitely recommend replacing all of the filters and the suggestion for the 75 was a good one

Good luck!

Unresistible Blue · 04/15/2006, 03:24 AM

A good rule of thumb is to replace your sediment filter and carbon block after six months. A more precise way to maximize the useable life of these two filters is to use a pressure gauge to identify when pressure reaching the membrane starts to decline. This is your indication one or both of the filers is beginning to clog.

Also be cognizant of the chlorine capacity of the carbon block. The Matrikx+1 (Ã¢â‚¬Å“Chlorine GuzzlerÃ¢â‚¬Â) for example will remove >90% of chlorine from 20,000 gallons of tap water presented at 1 gpm. Original equipment suppliers commonly provide carbon cartridges rated at 2,000 to 6,000 gallons.

Regarding your RO membrane and DI resin, use your TDS meter to measure, record, and track the tds (expressed in parts per million) in three places:
1. Tap water
2. After the RO but before the DI
3. After the DI.

The TDS in your tap water will likely range from about 50 ppm to upwards of 1000 ppm. Common readings are 100 to 400. So for sake of discussion, let's say your tap water reads 400. That means that for every million parts of water, you have 400 parts of dissolved solids. How do we go about getting that TDS reading down to somewhere near zero?

If you do some experimenting with your TDS meter, you'll note that your sediment filter and carbon block filter do very little to remove dissolved solids. So with your tap water at 400 ppm, you can measure the water at the in port on your RO housing and you'll see its still approximately 400 ppm.

The RO membrane is really the workhorse of the system. It removes most of the TDS, some membranes to a greater extent than others. For instance, 100 gpd Filmtec membranes have a rejection rate of 90% (i.e., they reject 90% of the dissolved solids in feed water). So the purified water coming from your 100 gpd membrane would be about 40 ppm (a 90% reduction). Filmtec 75 gpd (and below) membranes produce less permeate, but have a higher rejection rate (98%). The life span of a RO membrane is dependant upon how much water you run through it, and how dirty the water is. Membranes can function well for a year, two years, or more. To test the membrane, measure the total dissolved solids (TDS) in the water coming in to the membrane, and in the purified water (permeate) produced by the membrane. Compare that to the membraneÃ¢â‚¬â„¢s advertised rejection rate, and to the same reading you recorded when the membrane was new. Membranes also commonly produce less water as their function declines.

After the RO membrane, water will flow to your DI housing. DI resin in good condition will reduce the 40 ppm water down to 0 or 1 ppm. When the DI output starts creeping up from 0 or 1 ppm to 3 ppm, 5 ppm, and higher, you know that your resin needs to be replaced. Sometimes people complain that their DI resin didn't last very long. Usually the culprit is a malfunctioning RO membrane sending the DI resin dirty water. This will exhaust the resin quicker then would otherwise have been the case.

purelyh2o · 04/15/2006, 11:02 AM

Well written

You looking for a job?

J/K

smleee · 04/15/2006, 08:49 PM

One thing to remember is that even if you want to "maximize" the usable life of the prefilters they should be replaced at 6 months regardless of their performance; they can harbor bacteria and viruses and replacing them is even more important when using the unit for drinking.

eee

04/14/2006, 12:50 PM	#1
Kkubiak Registered Member Join Date: Apr 2006 Location: Giddings Tx Posts: 96	R/O Machine How do you know when it is time to change the filters on the R/o machine. I have a kent marine but I am not sure what model. It has two chambers underneath and a top tube which I think is the deionizing chamber. It has probably been 6 years since I used it to make salt water. Do you ever need to change the top canister or just the bottom two. Also is it a good brand to use in a reef aquarium.

04/14/2006, 02:52 PM	#6
bertoni RC Mod Join Date: Mar 2002 Location: Mountain View, CA, USA Posts: 88,616	I use a TDS meter to monitor the quality of the water from my RO-DI unit. That's a reasonable way to know how it's doing. __________________ Jonathan Bertoni

04/14/2006, 06:02 PM	#9
bertoni RC Mod Join Date: Mar 2002 Location: Mountain View, CA, USA Posts: 88,616	http://www.reefkeeping.com/issues/20...ture/index.php That articles talks about TDS. The TDS meters we use measure conductivity, which is an indication of the number of charged ions in the water. __________________ Jonathan Bertoni

04/15/2006, 12:04 AM	#11
purelyh2o Registered Member Join Date: Oct 2005 Location: Altamonte Springs, FL Posts: 454	:) 6 years..wow Time to change the rubber on the car... After 6 years I would definitely recommend replacing all of the filters and the suggestion for the 75 was a good one Good luck!

04/15/2006, 11:02 AM	#13
purelyh2o Registered Member Join Date: Oct 2005 Location: Altamonte Springs, FL Posts: 454	Unresistible Blue Well written You looking for a job? J/K

04/14/2006, 01:18 PM	#2
kau_cinta_ku Moved On Join Date: May 2005 Location: NW Iowa Posts: 8,669	is it an ro unit or rodi unit? the 2 canisters on the bottom are your sediment and carbon cartridges and the top i am guessing is the membrane if it has been 6 years i would change all the filters. the carbon and sediment need to be changed every 6 monthes regardless and the membrane about every 2 years

04/14/2006, 01:24 PM	#3
smleee Registered Member Join Date: May 2004 Location: Boise, ID Posts: 1,344	Yes the prefilters need to be changed every 6 months regardless. The membrane needs to be changed when the rejection ratio (you need a TDS meter for this) falls below a certain range compared to a new membrane, this varies with the make of membrane. For instance, if you have a 75GPD Dow FilmTec membrane the rejection ratio is 98%; when you drop to about 90% you want to change it. As said you should replace the membrane, without proper storage care the membrane is not good to use anymore. Do you think you can post a pic of it or maybe one that looks like yours? eee

04/14/2006, 01:38 PM	#4
Kkubiak Registered Member Join Date: Apr 2006 Location: Giddings Tx Posts: 96	i think I will do like you say and replace them all. i tried to download pictures but they are to big, too many kb's.

04/14/2006, 02:00 PM	#5
smleee Registered Member Join Date: May 2004 Location: Boise, ID Posts: 1,344	What GPD is your unit? I would replace the membrane with a 75GPD Dow FilmTec membrane, these are the best performing membranes available. Depending on your current membrane you may have to change the flow restrictor. eee

04/14/2006, 04:57 PM	#7
Kkubiak Registered Member Join Date: Apr 2006 Location: Giddings Tx Posts: 96	Where can I find the Dow Film Tec and how do I change out the flow restrictor? It looks as if it is just a part but wherre would I find one? Also how does a TDS meter work and what does it tell me? Thanks for the help guys.

04/14/2006, 05:56 PM	#8
kau_cinta_ku Moved On Join Date: May 2005 Location: NW Iowa Posts: 8,669	go here and post a thread to Bryan he can set you up with all the filters and membrane stuff you need http://www.reefcentral.com/forums/fo...s=&forumid=420

04/15/2006, 03:24 AM	#12
Unresistible Blue Registered Member Join Date: Mar 2002 Posts: 1,029	A good rule of thumb is to replace your sediment filter and carbon block after six months. A more precise way to maximize the useable life of these two filters is to use a pressure gauge to identify when pressure reaching the membrane starts to decline. This is your indication one or both of the filers is beginning to clog. Also be cognizant of the chlorine capacity of the carbon block. The Matrikx+1 (Ã¢â‚¬Å“Chlorine GuzzlerÃ¢â‚¬Â) for example will remove >90% of chlorine from 20,000 gallons of tap water presented at 1 gpm. Original equipment suppliers commonly provide carbon cartridges rated at 2,000 to 6,000 gallons. Regarding your RO membrane and DI resin, use your TDS meter to measure, record, and track the tds (expressed in parts per million) in three places: 1. Tap water 2. After the RO but before the DI 3. After the DI. The TDS in your tap water will likely range from about 50 ppm to upwards of 1000 ppm. Common readings are 100 to 400. So for sake of discussion, let's say your tap water reads 400. That means that for every million parts of water, you have 400 parts of dissolved solids. How do we go about getting that TDS reading down to somewhere near zero? If you do some experimenting with your TDS meter, you'll note that your sediment filter and carbon block filter do very little to remove dissolved solids. So with your tap water at 400 ppm, you can measure the water at the in port on your RO housing and you'll see its still approximately 400 ppm. The RO membrane is really the workhorse of the system. It removes most of the TDS, some membranes to a greater extent than others. For instance, 100 gpd Filmtec membranes have a rejection rate of 90% (i.e., they reject 90% of the dissolved solids in feed water). So the purified water coming from your 100 gpd membrane would be about 40 ppm (a 90% reduction). Filmtec 75 gpd (and below) membranes produce less permeate, but have a higher rejection rate (98%). The life span of a RO membrane is dependant upon how much water you run through it, and how dirty the water is. Membranes can function well for a year, two years, or more. To test the membrane, measure the total dissolved solids (TDS) in the water coming in to the membrane, and in the purified water (permeate) produced by the membrane. Compare that to the membraneÃ¢â‚¬â„¢s advertised rejection rate, and to the same reading you recorded when the membrane was new. Membranes also commonly produce less water as their function declines. After the RO membrane, water will flow to your DI housing. DI resin in good condition will reduce the 40 ppm water down to 0 or 1 ppm. When the DI output starts creeping up from 0 or 1 ppm to 3 ppm, 5 ppm, and higher, you know that your resin needs to be replaced. Sometimes people complain that their DI resin didn't last very long. Usually the culprit is a malfunctioning RO membrane sending the DI resin dirty water. This will exhaust the resin quicker then would otherwise have been the case.

04/15/2006, 08:49 PM	#14
smleee Registered Member Join Date: May 2004 Location: Boise, ID Posts: 1,344	One thing to remember is that even if you want to "maximize" the usable life of the prefilters they should be replaced at 6 months regardless of their performance; they can harbor bacteria and viruses and replacing them is even more important when using the unit for drinking. eee