DI resin exhausted after 200 gallon of product water?

[Opus]

I wouldn't leave my RO/DI system under pressure all the time. I have never had any issued with turning the system completely off at the source when not in use. Canisters have been known to fail, leak or even explode over time if pressure is strong enough, and under pressure, if one fails and your not home, that would equal a ton of water on the floor...

True and I've also heard the back pressure will harm the RO membrane. That is why they make a kit for systems that are hooked up to float valves.

 

[Philipgonzales3]

Yes. The plumbing/housing is all generic. The filters are what make the difference. My unit is a 25 year old Kent marine system that originally was a 24 gpd unit. I've upgraded over the years and currently have a 90 gal spectrapure 99% rejection rate RO membrane and I use their .2 micron prefilter. I added a second canister I got from BRS a few years ago so I could have a second carbon filter to protect my membrane since you never know when a city might decide to start adding chlormines to the water. Also added a canister many years ago so I could have a DI stage. Only thing you might have to change out is the flow restrictor. They are tuned to the gpd of the membrane. I have the one that that you stick in the tubing of the waste line and it can be trimmed to fine tune it.

FYI, your city website should have a link to the latest water report for your area. That will give you an indication of what is in your water.

Here is my water quality report.

https://www.saws.org/Your_Water/WaterQuality/Report/docs/2018_SAWS_Main_System.pdf

 

[mfinn]

It was taken right after the unit was turned on. I will let it run for at least 5 minutes and test again.

Not sure if you have a flush kit, but it help get the tds down, before going into the di resi by running water for 5-6 minutes.

 

[Philipgonzales3]

@Opus

So I ran my water into a bucket for 15 minutes.

Right after the RO and before the DI I am now getting 11ppm tds.

Source water 229.

Product water 1ppm.

I am thinking at the very least I should get a Tee and a ball valve and run the RO water for 15 minutes or so to waste water before running production water.

I can see how long the resin lasts this time. I'll also likely replace the RO membrane with a different brand also.

I also reseated the membrane and was getting 60ppm on startup still.

 

[Philipgonzales3]

I am in San Antonio (city water) also and have a different set up than you so I'll leave the advice to others but I will give you my setup that is working successfully.

First, I have a Jason's Water Softener { https://www.jasonswatersofteners.com/ } plumbed in for the whole house so I am sure that is going a good ways toward improving my water. Then I have a BRS 6 stage after that. I did discover over time that in my case for the DI only the Anion portion gets used up. So, I still keep one DI canister with the Cation at this time and just replace the Anion cylinder as it gets used up. This keeps me with O TDS, no struggle. The Prefilters before the DI I have yet to replace after 6 months and they still look good, though I feel I should probably replace them. But I will probably wait until I'm having trouble keeping O TDS.

Maybe this info will help some. With our water coming out of the underground aquifer it is "hard" water to start off with.....

It looks like I can order an extra DI canister. I think I will do this also. Run one with Cation and one with Anion.

 

[Opus]

Once you get the the Tee setup, you might want to run a test to see how long you need to let it run before it settles down. Most people only let it run for a few minutes before switching over to the DI. Maybe test it at 2 minutes and then 5 and then 10 and see what you get. You may be able to just have to do 2 or 3 minutes.

Your right at 95% rejection rate so it is up to you if you want to spend the money for a better membrane or just hold off awhile. Depending on how much water you are making, it might take a year or 2 for you to break even on buying a new one now.

 

[Opus]

It looks like I can order an extra DI canister. I think I will do this also. Run one with Cation and one with Anion.

I would just get the one from BRS for $16.99. You will also need a cartridge to put the DI in. Depending on usage, you may be better off buying the bulk package. For me it is just easier to buy 1 refill at a time since it takes me over a year to use up a cartridge. Also, I've gone to the non color changing since IMO it really doesn't work. Mine would change colors but it would be several months before I would actually see tds above 0 coming of it.

 

[Bradley Keck]

I wouldn't leave my RO/DI system under pressure all the time. I have never had any issued with turning the system completely off at the source when not in use. Canisters have been known to fail, leak or even explode over time if pressure is strong enough, and under pressure, if one fails and your not home, that would equal a ton of water on the floor...

Well, you might want to check with some of the people who make and install these systems for a living, like Buckeye Hydro, who recommend to do just that. The pressure coming in is not nearly enough to cause an explosion or something crazy, I have never heard of such a thing, and I can tell you that since installing a running the system in this fashion, I have had zero problems with my RODI unit and no explosions either

 

[CC13]

Well, you might want to check with some of the people who make and install these systems for a living, like Buckeye Hydro, who recommend to do just that. The pressure coming in is not nearly enough to cause an explosion or something crazy, I have never heard of such a thing, and I can tell you that since installing a running the system in this fashion, I have had zero problems with my RODI unit and no explosions either

..... I don’t need to ask Buckeye Hydro on whether a RO/DI Unit can leak under pressure because it absolutely can. I have had it happen before. I have 70 PSI from my city water hookup and your not going to find anyone that is willing to state that’s not enough pressure for a leak to spring from a worn O-ring or fitting. It absolutely can so I’m not sure who you got that information form but they weren’t a reliable source.

You may do as you like good sir, the majority of us turn the water off to the RO/DI units, there is absolutely nothing wrong with turning the water off, so why on earth would you risk a flood for zero benefit whatsoever.

And for the record, canisters explode all the time. People hookup booster pumps, without adjusting the booster properly or without using a pressure gauge. What do you think happens when your running 120+ PSI through your RO unit lol

 

[Bradley Keck]

..... I don’t need to ask Buckeye Hydro on whether a RO/DI Unit can leak under pressure because it absolutely can. I have had it happen before. I have 70 PSI from my city water hookup and your not going to find anyone that is willing to state that’s not enough pressure for a leak to spring from a worn O-ring or fitting. It absolutely can so I’m not sure who you got that information form but they weren’t a reliable source.

You may do as you like good sir, the majority of us turn the water off to the RO/DI units, there is absolutely nothing wrong with turning the water off, so why on earth would you risk a flood for zero benefit whatsoever.

And for the record, canisters explode all the time. People hookup booster pumps, without adjusting the booster properly or without using a pressure gauge. What do you think happens when your running 120+ PSI through your RO unit lol

I'm certainly not an expert and didn't mean to get you all worked up Just trying to help the OP. I would defer to those who have more experience with these systems than your average reefer. In my case, my BRS 6 stage worked great for the first 200g of product water, and then all of sudden I am getting crazy TDS readings. Long story short, I had to replace the membrane housing, pressure regulator valve, and defective membrane(not related). I had several people on R2R help me figure out what was wrong and get it working again, and I would consider them excellent sources of help. One thing they told me was that shutting off the water supply and then turning it on again is harder on the system and leads to leaks more than keeping it under a constant pressure. Mine stays at 55 to 60PSI all the time now and all I do is start the flow back up from the ball valve. I'm sure there ar plenty of people who shut off their water supply and have no issues, but that was not me and under relatively lower pressure. I have now made well over 600g of RODI without any issues. I disagree that it would be crazy to leave the water supply on as many auto WC systems do just that in order to keep constant supply of RODI going. I suppose anything can spring a leak that is hooked to water, but I'm not going to shut off my main to my house every night out of fear of that happening, and you bring up a good point that if you have crazy amounts of pressure, I suppose something could bust/explode. I did not realize it happens all the time.. kind of makes me scared of my RODI unit now. If anyone would like, you can look up my thread from when I was having trouble. "Help my TDS is through the roof and so is my DI resin budget" To the OP, 11 TDS after the RO is actually pretty darn good! I get 8 now and do not go through nearly as much DI resin. Hope it works out well for you. Happy reefing!

 

[Buckeye Hydro]

Hi guys.

First, let's define rejection rate - it is the % of TDS that the membrane DOES NOT allow to pass through. The higher the rejection rate, the longer your DI life.

With the last set of reading you provided (tap @ 229, RO @ 11), let's go through the math to calculate your rejection rate. Easy calcs and there's no complex algorithm to noodle through.
It's calculated this way:
1-(RO TDS / tap water TDS); so in your case
1 - (11/229) =
1 - (0.04) =
0.96 =
96%

There is a post above that said higher rejection membranes waste more water. That's not correct. People often confuse REJECTION RATE and RECOVERY.
"Recovery" is another way of looking at what people in this hobby call the "waste to purified water ratio." Recovery is easy to calculate as well, and you'll see the calculation does not include any TDS readings:
RECOVERY = the percent of the feedwater that ends up as RO water (aka "permeate")
So no doubt you've heard of the proverbial 4 to 1 ratio of waste water to RO water. Let's calculate the recovery for that:
5 gallons of feedwater produces 4 gallons of concentrate and 1 gallon of permeate.
1/5 = 20% recovery.

As an example, Filmtec residential scale ("1812") membranes used in this hobby are factory tested at 50 psi, 77F, and 15% recovery - that's a 5.5 to 1 ratio.

Russ

 

[Buckeye Hydro]

Bradley Keck - by a "pressure regulator" are you referring to a pressure gauge? A flow restrictor? Most residential size RO or RODI units do not have a component called a "pressure regulator" on them.

Russ

 

[Buckeye Hydro]

Regarding systems "exploding" due to pressure... And I'm talking about a sudden catastrophic failure, not a slow leak/drip.

Can it happen? Sure.
Is it common? No.

In most residential-scale systems in this hobby, there is one component that is typically the weakest in its ability to withstand pressure. Any guesses what that component is? And what causes it to fail?

Russ

 

[alton]

Okay Russ how long do we need wait for the answer?

 

[Buckeye Hydro]

Let's wait for a few more people to get out of bed! Lol. The answer is (IMO) pretty important in that it affects how many people configure their systems, and some common maintenance everyone does.

 

[homer1475]

I'm guessing the flow restrictor, or orings on the canisters. I've had a couple fail over the years.

 

[alton]

Hey Russ what eve happened to you snooze you lose? To the OP since you are in SA, depending where you are at your TDS by summer should be back to 400 when the Edwards Aquifer goes below normal. Right now with all the recent rains the Limestone aquifer is pretty diluted. I would spend the extra money and try a new membrane and run 50 to 60 gallons at a time stored in a food grade barrel. Turning a RO/DI on and off every 5 to 10 gallons burns through DI. FYI I live in East Bexar county and my TDS this weekend was at 255 and before DI was 5ppm.

 

[Buckeye Hydro]

Nope, but replacing housing orings is a common task everyone should be doing. Remove, clean, lube with food grade silicone grease, and replace every time you change your filters, and always have extra orings on hand.

Russ

 

[Buckeye Hydro]

In most residential-scale systems in this hobby, there is one component that is typically the weakest in its ability to withstand pressure. Any guesses what that component is? And what causes it to fail?
Russ

Well alrighty then... I'm referring to the clear housings.

Rather than lube orings regularly and change orings as needed, we find that if housings leak a lot of people will grab their housing wrench and go to town. Not a good approach. What you're risking:

When you tighten the housing you are pulling UP on the threads, and pushing DOWN on the oring and the rest of the housing.

Russ

 

[Buckeye Hydro]

This is the main reason Buckeye specifies that booster pumps should be installed AFTER all the prefilter housings and after a little strainer. This placement avoids exposing prefilter housings to elevated pressure.

(PREFILTER = any filter that touches the feedwater prior to the RO membrane)

Russ