How long does your RO/DI last?

Loki · Jun 20, 2012

I have had my 5 stage typhoon III RO/DI unit from AirWaterIce.com for 7 months now. It is still reading 0 TDS.

My tap water is 92tds

I have a system with 150 gallons of water, 16 gallon bowfront, 29 hospital tank, and I use my DI bypass to make drinking water for my water dispenser. So I know I have used a lot of water. I have yet to change any filters. I have a complete set ready to go when the time comes.

How long do you get out of your unit before having to change anything? What order do you replace your filters?

wysiwyg · Jun 20, 2012

my filters say 5000g to 10000g depending on the amount of tds in your water

wysiwyg · Jun 20, 2012

and i replace all my filters at the same time

AZDesertRat · Jun 21, 2012

You cannot go by what filters say on them, that is or 2,000 treated gallons at the normal 4:1 waste ratio the carbon is exhausted. That is also assuming you are using a high quality sediment filter with the same micron rating or smaller as the carbon block is. By this I mean a 10 micron sediment filter does very little to protect a 5 micron or 1 micron carbon block since it passes particles which plugs or fouls the carbons billions of tiny microscopic pores which is where the chlorine is adsorbed rendering it useless.

This is why it is best to use a 1.0 or 0.5 micron absolute rated sediment filter and a 0.5 micron absolute rated carbon block so they do the best job of protecting your expensive RO membrane so it in trun can protect your expensive DI resin.

That being said, I use a pleated 0.2 micron absolute rated sediment filter which has 10x the surface area or a normal spun poly sediment filter and even though it filters many times finer, it lasts longer and has less head loss or pressure drop. That is followed by a 0.5 micron 20,000 gallon carbon block and a 90 GPD RO membrane operating on a booster pump at 100 psi to produce 120 GPD at 1:1 waste ratio with a microprocessore controlling backwashes with stored DI water then pickling or storing the system in DI while it is sitting dormant. This is followed by a dual DI system which pumps into a 23 gallon storage container.
The sediment and carbon block are monitored by two pressure gauges for plugging or head loss and I also use a low range chlorine test kit so I can extend their life out to 18 months easily with less than a 2 psi pressure loss and no chlorine break thru. The membrane is over 4 years old and still operating at 99.43% efficiency or rejection rate. The DI lasts over a year on the first one, over 1100 measured gallons and about 3 years on the second one or about 3,500 gallons. My tap water TDS runs between 550 and 850 depending on the seasons and the blends of source water from the Colorado, Salt, Verde and Agua Fria Rivers. The RO only TDS runs between 2 and 3 and of course both DI TDS readings are 0 using a HM Digital COM-100 TDS meter.

When I owned a Typhoon III all I could get was 150 gallons per DI refill no matter what I did and whose resin I used. I was less than happy so switched brands of RO/DI and the DI life went up 5 or 6 times. By using better high quality low micron absolute rated sediment and carbon my membrane should easily last 10+ years. There really is a difference in systems even though many look similar. You get what you pay for and cheap is not where you want to be.

Ace25 · Jun 21, 2012

I get 300G out of a DI canister due to extremely high TDS source water. I get about 2000G out of my RO membrane. Other filters vary and are replaced at proper stages.

Loki · Jun 21, 2012

I would estimate that I am pushing 750-1000 gallons so far. Yesterday alone I used 55 still pushing out 0 tds. I just wanted to see if this was normal or not. maybe I'll take my TDS meter somewhere and compare it with someone elses.

Loki · Jun 21, 2012

wysiwyg said:
and i replace all my filters at the same time

even your RO membrane?

KSzegi · Jun 22, 2012

Ace25 said:
I get 300G out of a DI canister due to extremely high TDS source water. I get about 2000G out of my RO membrane. Other filters vary and are replaced at proper stages.

About the same here .... sometimes i can't even get 300gallons out of the di .....

strange33w · Jun 22, 2012

I got around 750 out of mine before I had to change it. My water from the tap is around 93

Steelerfan747 · Jun 22, 2012

AZDesertRat said:
You cannot go by what filters say on them, that is or 2,000 treated gallons at the normal 4:1 waste ratio the carbon is exhausted. That is also assuming you are using a high quality sediment filter with the same micron rating or smaller as the carbon block is. By this I mean a 10 micron sediment filter does very little to protect a 5 micron or 1 micron carbon block since it passes particles which plugs or fouls the carbons billions of tiny microscopic pores which is where the chlorine is adsorbed rendering it useless.

This is why it is best to use a 1.0 or 0.5 micron absolute rated sediment filter and a 0.5 micron absolute rated carbon block so they do the best job of protecting your expensive RO membrane so it in trun can protect your expensive DI resin.

That being said, I use a pleated 0.2 micron absolute rated sediment filter which has 10x the surface area or a normal spun poly sediment filter and even though it filters many times finer, it lasts longer and has less head loss or pressure drop. That is followed by a 0.5 micron 20,000 gallon carbon block and a 90 GPD RO membrane operating on a booster pump at 100 psi to produce 120 GPD at 1:1 waste ratio with a microprocessore controlling backwashes with stored DI water then pickling or storing the system in DI while it is sitting dormant. This is followed by a dual DI system which pumps into a 23 gallon storage container.
The sediment and carbon block are monitored by two pressure gauges for plugging or head loss and I also use a low range chlorine test kit so I can extend their life out to 18 months easily with less than a 2 psi pressure loss and no chlorine break thru. The membrane is over 4 years old and still operating at 99.43% efficiency or rejection rate. The DI lasts over a year on the first one, over 1100 measured gallons and about 3 years on the second one or about 3,500 gallons. My tap water TDS runs between 550 and 850 depending on the seasons and the blends of source water from the Colorado, Salt, Verde and Agua Fria Rivers. The RO only TDS runs between 2 and 3 and of course both DI TDS readings are 0 using a HM Digital COM-100 TDS meter.

When I owned a Typhoon III all I could get was 150 gallons per DI refill no matter what I did and whose resin I used. I was less than happy so switched brands of RO/DI and the DI life went up 5 or 6 times. By using better high quality low micron absolute rated sediment and carbon my membrane should easily last 10+ years. There really is a difference in systems even though many look similar. You get what you pay for and cheap is not where you want to be.

What brand of system are you using. I have been thinking of getting one and would like to look into something dependable

AZDesertRat · Jun 22, 2012

SpectraPure Water Purification Products
They have been doing reef quality RO/DI for over 25 years in Tempe AZ the whole time.
If any of you are familiar with Freshwater and Marine Aquarium Magazine (FAMA its usually called) they have advertised in there forever.
They support many of the reef forums and have Sponsors sections to answer all your questions plus have been known to support local reef clubs. When I was President of my local club they donated things all the time and did many presentations to teach us all about RO/DI and water quality. They even have reef tanks in their offices. Its nice to support someone who supports the hobby.

At the top of their main page they have a reef quality system for only $128 that cannot be beat.
MAXPURE MPDI SYSTEM
0.5 micron absolute rated sediment filter, 0.5 micron 20,000 gallon carbon block, a 90 GPD specially treated and batch tested high rejection rate RO membrane, a full size 20 oz vertical DI filter filled with reef specific custom blended SilicaBuster DI resin, am inline pressure gauge and a capillary tube flow restrictor you yourself adjust according to your unique conditions. You won't find anything close at any price.

azjohnny · Jun 22, 2012

AZDesertRat said:
SpectraPure Water Purification Products
They have been doing reef quality RO/DI for over 25 years in Tempe AZ the whole time.
If any of you are familiar with Freshwater and Marine Aquarium Magazine (FAMA its usually called) they have advertised in there forever.
They support many of the reef forums and have Sponsors sections to answer all your questions plus have been known to support local reef clubs. When I was President of my local club they donated things all the time and did many presentations to teach us all about RO/DI and water quality. They even have reef tanks in their offices. Its nice to support someone who supports the hobby.

At the top of their main page they have a reef quality system for only $128 that cannot be beat.
MAXPURE MPDI SYSTEM
0.5 micron absolute rated sediment filter, 0.5 micron 20,000 gallon carbon block, a 90 GPD specially treated and batch tested high rejection rate RO membrane, a full size 20 oz vertical DI filter filled with reef specific custom blended SilicaBuster DI resin, am inline pressure gauge and a capillary tube flow restrictor you yourself adjust according to your unique conditions. You won't find anything close at any price.

I have the same $128 unit with a booster pump that I also run at 100psi and it is fantastic!...IMO if your incoming water pressure is below 60 psi I would get a booster pump, mine is just under40 and I tried the filter without the booster pump and it was very slow.

Also if you have hard water I would suggest running a water softener before the RO/DI, salt is easier on the filter than calcium

Loki · Jul 7, 2012

I changed out the filters last week. I got a reading of 3-4 TDS. So I dumped the 55 gallons of water I had and started over

. I will now try to keep a better track of how many gallons I use before filter changes.

mfinn · Jul 8, 2012

azjohnny said:
I have the same $128 unit with a booster pump that I also run at 100psi and it is fantastic!...IMO if your incoming water pressure is below 60 psi I would get a booster pump, mine is just under40 and I tried the filter without the booster pump and it was very slow.

I was under the impression that ro/di untis shouldn't be operated at more than 80 psi.
Are there different specs for different membranes?

AZDesertRat · Jul 8, 2012

Membranes actually perform better at higher pressures up to about 150 psi. The limiting factor are the fittings and housings which if made in the US and carrying an ANSI/NSF and or UPC rating will have an operating pressure of 125 psi.
Vendors tell you 60-80 psi for liability reasons.
Increased pressure not only gives you much higher GPD but it also improves the rejection rate or removal efficiency so DI lasts longer and it costs less to own and operate.

mfinn · Jul 8, 2012

So I guess I can bump up the pressure on my pump.

Thanks

AZDesertRat · Jul 8, 2012

If you have a quality system with good name brand canisters and john guest style fittings then yes. If you have an ebay type system I would be very cautious as the housings are rarely UPC approved and may burst or leak. There is wide variety of qualities on the market and thye way ebay vendors cut costs is with knock off components and filters tha tlook the same but rarely are in reality.

mfinn · Jul 21, 2012

I bumped up the pressure from 80psi to about 98psi and the difference was huge.
I didn't do a timed test, but it seemed like my 30 gallon top-off container filled twice as fast, as it did when the pressure was lower, when I drained it for a water change.

AZDesertRat · Jul 21, 2012

Not only will it increase the GPD significantly but it will also improve the removal efficiency or rejection rate also meaning your DI will last much longer. You will want to check your waste ratio though as it may need adjusting to fit the higher pressure.