I have that FilterGuys unit pictured above myself. They said if you're experienced it might have one or so extra filters but for new people it's more safe... just in case you don't change your filters when you are supposed too. It's a good unit for me till I become an expert with it. I have a hard time remembering what you're supposed to do with this part of reefkeeping b/c you don't think about it for months. So I like the extra protection... that's why it's $199. 5-stage.
ro/di unit
- Thread starter ALEXEY70
- Start date
Good information... I have yet to purchase my RO unit but this will be done before I set up my tank. I have been out of the hobby for 10 years and always said if I ever do it again this is a must have piece of equipment.
I’m a little confused on the stages everyone is talking about can someone clarify the RO process?
I understand the basic operation but more clarification would help people like me choose what type to purchase.
Also clarification on how often you need to change filters
Do most units have a connection so I can connect to a garden hose faucet?
I’m a little confused on the stages everyone is talking about can someone clarify the RO process?
I understand the basic operation but more clarification would help people like me choose what type to purchase.
Also clarification on how often you need to change filters
Do most units have a connection so I can connect to a garden hose faucet?
Buckeye Field Supply
Sponsor
- Location
- On the Internet
Unless you have unusual tap water, we recommend a 4-stage RODI system. Although many systems are available on the market with more than 4 stages, including many that we consider poorly configured - especially on the auction website, these additional stages are not needed, and when configured poorly, can do more harm than good.
So what are the 4 stages? In order of water flow:
Sediment filter, to
Carbon block (not GAC!), to
RO membrane, to
Deionization ("DI") stage.
If you do have unusual tap water, additional stages, or filters larger than typical, are available to deal with almost any situation. Some common situations include:
heavy sediment loads
chloramines
high CO2
high TDS
iron
manganese
hydrogen sulfide
Again assuming that you have "typical" tap water, let's talk a little about about each of the 4 recommended stages.
Sediment filter: we recommend a poly depth filter, with a 1 micron pore size.
Carbon block: go with a 0.5 micron, 20,000 gallon block.
RO Membrane: Nearly all membranes sold into this market are "TFC" membranes. Numerous options are available based upon the capacity of the membrane. Common capacities include 24 gallons per day, 50 gpd, 75 gpd, 100 gpd, and 150 gpd. Check the water pressure recommendations before you buy, and compare that to what you have in your house.
DI resin: A refillable cartridge filled with high quality mixed bed resin works best for most people.
Russ
So what are the 4 stages? In order of water flow:
Sediment filter, to
Carbon block (not GAC!), to
RO membrane, to
Deionization ("DI") stage.
If you do have unusual tap water, additional stages, or filters larger than typical, are available to deal with almost any situation. Some common situations include:
heavy sediment loads
chloramines
high CO2
high TDS
iron
manganese
hydrogen sulfide
Again assuming that you have "typical" tap water, let's talk a little about about each of the 4 recommended stages.
Sediment filter: we recommend a poly depth filter, with a 1 micron pore size.
Carbon block: go with a 0.5 micron, 20,000 gallon block.
RO Membrane: Nearly all membranes sold into this market are "TFC" membranes. Numerous options are available based upon the capacity of the membrane. Common capacities include 24 gallons per day, 50 gpd, 75 gpd, 100 gpd, and 150 gpd. Check the water pressure recommendations before you buy, and compare that to what you have in your house.
DI resin: A refillable cartridge filled with high quality mixed bed resin works best for most people.
Russ
Buckeye Field Supply
Sponsor
- Location
- On the Internet
How often should the various filters be replaced? This has to be our single most frequently asked question.
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 filters is beginning to clog.
Also be cognizant of the chlorine capacity of the carbon block. The Matrikx+1 (“Chlorine Guzzler”) for example will remove 99% 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 parts per million (ppm). Common readings are 100 to 400 ppm. So for sake of discussion, let's say your tap water reads 400 ppm. 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 (collectively called “prefilters”) 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 it is 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 purified water (aka “permeate”), but have a higher rejection rate (96 to 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 membrane’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, you know that your resin needs to be replaced. Sometimes people complain that their DI resin didn't last very long. Often the culprit is a malfunctioning RO membrane sending the DI resin “dirty” water. This will exhaust the resin quicker than would otherwise have been the case. Sometimes the problem is poor quality resin – remember that all resins are not created equal!
Russ
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 filters is beginning to clog.
Also be cognizant of the chlorine capacity of the carbon block. The Matrikx+1 (“Chlorine Guzzler”) for example will remove 99% 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 parts per million (ppm). Common readings are 100 to 400 ppm. So for sake of discussion, let's say your tap water reads 400 ppm. 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 (collectively called “prefilters”) 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 it is 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 purified water (aka “permeate”), but have a higher rejection rate (96 to 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 membrane’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, you know that your resin needs to be replaced. Sometimes people complain that their DI resin didn't last very long. Often the culprit is a malfunctioning RO membrane sending the DI resin “dirty” water. This will exhaust the resin quicker than would otherwise have been the case. Sometimes the problem is poor quality resin – remember that all resins are not created equal!
Russ
The Spectrapure ProPlus found here for $149 is the best value in a reef quality RO/DI today.
http://www.spectrapure.com/email/custom ... ion.html#1
My second choice, and probably the only other vendor I would consider is the 75 GPD Premium from Buckeye. Russ is a great guy.
http://www.spectrapure.com/email/custom ... ion.html#1
My second choice, and probably the only other vendor I would consider is the 75 GPD Premium from Buckeye. Russ is a great guy.
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