My New RO/DI Setup

[Blufgan]

I just finished getting my new RO system setup let me know what you think. Here are my specs. 200 micron prefilter going in to my booster pump from my source water,4 stage system, 1 micron sediment prefilter, AquaFx booster pump with pressure switch, 5 micron carbon block, 100 gpd Dow Filmtec membrane, 100 psi liquid filled pressure gauge, going in to my membrane, ASV, color change nuclear grade di resin,and membrane flush valve. Here are some pics.

 

[revsgirl]

Looks like you did a great job!

 

[Blufgan]

Looks like you did a great job!

Thanks I've been thinking,about doing one like this for a while.

 

[AZDesertRat]

Unfortunately the 100 GPD Dow Filmtec membrane is the worst possible choice of all membranes on the market. In fact it is not even a reverse osmosis or RO membrane at all but is considered by the ANSI/NSF to be a nano filter or NF not RO. This means it is not rated for drinking water use in the US since it is only 90% rejection rate versus 96-98% rejection rate for the 75 GPD and smaller versions. This is critical since for every 2% you reduce the rejection rate you cut your DI resin life in half, imagine how much longer your DI would last at 98% versus 90% ?

An even better option would be a Spectrapure SpectraSelect specially treated then individually hand tested 90 GPD high rejection rate RO membrane which is guaranteed in writing to be better than 98% rejection rate. Mine is averaging over 99.4% rejection even after 4.5 years of usage so DI lasts a long long time. For $45 for the membrane and $5 for a matched capillary tube flow restrictor you can't go wrong.

I would also swap the 1 micron sediment filter for a 0.5 micron absolute sediment filter and the 5.0 micron 6,000 gallon carbon block for a 0.5 micron 20,000 gallon carbon block so you do a much better job of protecting your expensive RO membrane which is the workhorse of the system and in turn makes your DI last longer and work better. You have to look at it like a complete system, start to finish and each component has an effect on whatever follows it.

Next, once the DI is exhausted replace it with non color changing resin since color change is a horrible indicator of condition and very inaccurate. It can change in streaks, top to bottom, bottom to top, not at all, all at once etc. It should also be in a full size 20 oz vertical refillable DI not horizontal which leads to short circuiting or channelling for poor treatment. Remount what you have vertically for now so it fills from the bottom up for better DI life and water quality. Use only a hand held TDS meter such as the HM Digital TDS-3, TDS-4TM or COM-100 to test with as inlines are not very accurate and not temperature compensated so can be off significantly if your water temperature and air temperature are not exactly the same which they rarely are.

There really is no need to build your own system when you can buy a guaranteed 150 GPD system brand new for $150 or the absolute best system on the planet for $269. If pressures are low you can add a booster pump to any system but I would personally stick with an Aquatec 8800 pump as they are the industry standard unlike all the imports flooding the market.

Anoter system you might look at for quality filters and components is the 75 GPD Premium from Buckeye Field Supply, $169 and it includes a handheld TDS meter, DI bypass valve, capillary tube flow restrictor, low micron filters and even a thermometer. Buckeye will try their best to talk you out of a 100 GPD Dow as they know its intended use per the NSF.

Be very careful with those canister lids you have, I have had trouble with hairline cracks right where the nipple screws in even at normal un-boosted pressures. On my inexpensive drinking water system I ended up going to Spectrapure for new replacements as the lids they use are much heavier duty and have twice the plastic thickness around the threaded areas. Many found today are not ANSI/NSF or uniform plumbing code rated and are imported using inferior plastcis, at work we went through dozens of them before switching to Pentek brand which is probably what I replaced mine at home with if I looked.

I like how you mounted it all to make it truly portable but I think I would have purchased a larger top bracket and mounted it all on there. More like this which is my system:

 

[Blufgan]

Unfortunately the 100 GPD Dow Filmtec membrane is the worst possible choice of all membranes on the market. In fact it is not even a reverse osmosis or RO membrane at all but is considered by the ANSI/NSF to be a nano filter or NF not RO. This means it is not rated for drinking water use in the US since it is only 90% rejection rate versus 96-98% rejection rate for the 75 GPD and smaller versions. This is critical since for every 2% you reduce the rejection rate you cut your DI resin life in half, imagine how much longer your DI would last at 98% versus 90% ?

An even better option would be a Spectrapure SpectraSelect specially treated then individually hand tested 90 GPD high rejection rate RO membrane which is guaranteed in writing to be better than 98% rejection rate. Mine is averaging over 99.4% rejection even after 4.5 years of usage so DI lasts a long long time. For $45 for the membrane and $5 for a matched capillary tube flow restrictor you can't go wrong.

I would also swap the 1 micron sediment filter for a 0.5 micron absolute sediment filter and the 5.0 micron 6,000 gallon carbon block for a 0.5 micron 20,000 gallon carbon block so you do a much better job of protecting your expensive RO membrane which is the workhorse of the system and in turn makes your DI last longer andwork better. You have to look at it like a complete system, start to finish and each component has an effect on whatever follows it.

Next, once the DI is exhausted replace it with non color changing resin since color chan indicator of condition and very inaccurate. It can change in streaks, top to bottom, bottom to top, not at all, all at once etc. It should also be in a full size 20 oz vertical refillable DI not horizontal which leads to short circuiting or Wwwchannelling for poor treatment. Remount what you have vertically for now so it fills from the bottom up for better DI life and water quality. Use only a hand held TDS meter such as the HM Digital TDS-3, TDS-4TM or COM-
100 to test with as inlines are not very accurate and not temperature compensated so can be off significantly if your water temperature and air temperature are not exactly the same which they rarely ar

There really is no need to build your own system when you can buy a guaranteed 150 GPD system brand new for $150 or the absolute best system on the planet for $269. If pressures are low you can add a booster pump to any system but I would personally stick with an Aquatec 8800 pump as they are the industry standard unlike all the imports flooding the market.

Anoter system you might look at for quality filters and components is the 75 GPD Premium from Buckeye Field Supply, $169 and it includes a handheld TDS meter, DI bypass valve, capillary tube flow restrictor, low micron filters and even a thermometer. Buckeye will try their best to talk you out of a 100 GPD Dow as they know its intended use per the NSF.


Be very careful with those canister lids you have, I have had trouble with hairline cracks right where the nipple screws in even at normal un-boosted pressures. On my inexpensive drinking water system I ended up going to Spectrapure for new replacements as the lids they use are much heavier duty and have twice the plastic thickness around the threaded areas. Many found today are not ANSI/NSF or uniform plumbing code rated and are imported using inferior plastcis, at work we went through dozens of them before switching to Pentek brand which is probably what I replaced mine at home with if I looked.

I like how you mounted it all to make it truly portable but I think I would have purchased a larger top bracket and mounted it all on there. More like this which is my system:

Hi thanks for all the advice much appreciated. This is the second system I've built they both produce 0 TDS and thr di resin is not considered a tell tail
sign to change the DI resin I have several different TDS meters I get them from work . Now I understand opinions and respect them but an opinion . I'm a senior engineer at our local nuclear plant in Crystal River FL I work for OSHA water quality department so I'm constantly testing water all day and I hate burst a bubble but there is only a few companies that manufacture RO membranes and about 95% of them come from Dow including the ones that Spectrapure uses in their systems .
As does half the other RO/DI also horizontal di units provide maximum surface area used cutting back on di resin consumption we use much bigger ones at work
our systems are designed to monitor and treat millions of gallons of water that flow through our cooling towers a day . This water that we treat must be at 0 TDS as it re enters the near by river. I mean no disrespect but I went to MIT and the University of Florida to obtain my Masters in Aquatic engineering I don't know everything
but I do know water management and Dow Filters are pretty much a standard in my industry and unless your finding were wrote by an aquatic or mechanical engineer I look at them as pure opinion and not factual.

 

[AZDesertRat]

They may produce ) TDS from the RO/DI but what is the RO only rejection rate?

Your degrees don't impress me, I have 37+ years in water treatment myself and train operators and junior engineers for a living. Yes, I know where Spectrapure gets their membranes and I also know who makes most of them. Dow does not make 95% themselves but they do sell Dow Filmtec membrane fabric to other winders who wind their own membranes.

I will beg to differ with you on horizontal filters, a vertical with a bottom up configuration will outperform it every time. Water takes the path of least resistance and in a horizontal, atmospheric pressure application that is along the bottom leaving the top resin untouched.

DI resin life is directly affected by the membrane rejection rate, increase its efficieny and your DI life will go up significantly. Take a look at Dows cut sheets on the 100 and 75 GPD versions, you will see for yourself the 100 is not approved for drinking water as it does not have 3 log removal. it is a nano filter not a reverse osmosis membrane. I have improved hundreds of system for people over the last couple decades with no complaints so if you want syggestions that is fine, if not thats also OK but its your money.

 

[Blufgan]

It's funny how people think they know everything just cause they've been doing something for a while . I l asked my supervisor and he did agree with the 100 gal membrane is not fully considered as a RO filter and as you said a nano filter so I will probably replace it with two 75 gpd membranes however he agrees with the fact that majority of membranes come
from DOW and that DOW does not purchase membranes from other companies and they spin their membranes in house in Penn.

 

[AZDesertRat]

You misunderstood, I did not say Dow purchases membranes from others, what I did say was Dow sells membrane fabric on the market. They sell to others such as Applied membranes or maybe Koch who then wind their own membranes.

 

[jtl]

I need some help with my system. It has not worked very well from the get go (purchased from Purewaterclub.com) the membranes don't last over a year and the TDS is not much different than my tap water which is 180 ppm. Here are my specs: I have a 5 stage (sediment, (2) carbon block, membrane, and post filter). I also have a shut off valve, flow restrictor and a storage tank with air bladder in a 100gpd system. Since I need to replace all of the filters, maybe I should consider changing some things out. I am thinking I should go with a 75 gpd membrane matched with a new flow restrictor. I wonder if I need two carbon block filters and the post filter. Is the tank and the shut valve necessary, the tank is while it is full but it doesn't last long. Obtw, my incoming water pressure is about 55 psi. Any thoughts about what I should do?

 

[AZDesertRat]

For a reef system you do not want the pressure tank or the post RO GAC carbon filter as both cause TDS problems as you are experiencing.

It is very easy to isolate a RO only stream by using a 1/4" tee, check valve and ball valve between the RO membrane and the pressure tank so you can still have pressurized drinking water but have a seperate unpressurized line for making aquarium water.

It sounds like you do not have a DI filter so I would add one on this RO only line which again is a snap and has nothing to do with the pressurized drinking water side.

Look at this diagram and note the placement of the tee and ball valve for the reef water and how it is seperated from the pressure tank.

http://www.spectrapure.com/huds/4-STAGE-DWK-RODI-NAG.pdf


Before replacing your RO membrane, try disconnecting the GAC taste and odor post carbon cartridge and pressure tank, let the RO run for an hour or so and take a TDS sample directly from the 1/4" treated water line. Also take a tap water sample at the same time so we can calculate your rejection rate or membrane efficiency. It may not be as bad as you think as the pressure tank and GAC carbon are more than likely causing your problems.

If it is in need of replacement I would highly recommend a Spectrapure treated and hand tested high rejection rate 90 GPD RO membrane, a 0.5 micron absolute rated sediment filter and a single 0.5 micron 20,000 gallon carbon block. You can then easily and cheaply replumb the extra unneeded carbon canister into a DI filter and add a refillable SilicaBuster DI cartridge and have a reef quality RO/DI as well as a drinking water system for less than $100. ($45 membrane, $5 matched flow restrictor, and $45 for the FILTKIT-3PK-CSPDI which is the sediment, carbon block and filled SilicaBuster refillable DI cartridge)

Everything is on the sale flyer towards the bottom here except the flow restrictor which is on their main web page for $5.
SpectraPure - Great Deals on All your Water Management needs!

Besides the above you would need another $10 or $15 for a 1/4" john guest style too, a 1/4" check valve and a 1/4" ball valve. You might be able to get all that at Lowes of Home Depot or any RO vendor should have them too. You should have what you need already to convert the extra carbon canister to a DI filter so there would be no extra cost there once you order the refillable DI cartridge in the kit.

Check your RO and tap water TDS first though as you may not need a new membrane yet and that saves you $50.

 

[scooterc268]

I need some help with my system. It has not worked very well from the get go (purchased from Purewaterclub.com) the membranes don't last over a year and the TDS is not much different than my tap water which is 180 ppm. Here are my specs: I have a 5 stage (sediment, (2) carbon block, membrane, and post filter). I also have a shut off valve, flow restrictor and a storage tank with air bladder in a 100gpd system. Since I need to replace all of the filters, maybe I should consider changing some things out. I am thinking I should go with a 75 gpd membrane matched with a new flow restrictor. I wonder if I need two carbon block filters and the post filter. Is the tank and the shut valve necessary, the tank is while it is full but it doesn't last long. Obtw, my incoming water pressure is about 55 psi. Any thoughts about what I should do?

55psi isn't bad, however, the higher the GPD on the membrane the higher pressure requirements. Keep the sediment filter 1st, carbon block afterwards, then that line feeds into the RO membrane. The output (not waste water line) then goes to the DI filter where the remaining TDS is removed. You would be better off with a dual DI chamber than a dual carbon block. Make sure you have the correct lines going where they need to go.

I have a flimtec 75GPD on a spectra pure RO/DI unit. Incoming pressure was about 40psi (I live in an apartment) which hindered the GPD. I added a RO booster pump and my pressure is 75psi. My TDS out the membrane is 3ppm with the booster pump w/o the booster pump was 14ppm. No flow restrictor either. My TDS out the tap is 180. Just food for thought.


Sent from my iPad using Tapatalk

 

[AZDesertRat]

Higher GPD membranes do not require higher pressures. All household type membranes, 15 to 100 GPD are rated such at 50 psi and 96-98% sustained rejection rate. That being said, higher pressures will make a membrane more efficient though but is not a requirement.

By plumbing as I suggested you get dual use out of the system, RO only for drinking via the isolated pressure tank and either unpressurized RO only or RO/DI for the tanks.