RO/DI decision time

['06Siguy]

<a href=showthread.php?s=&postid=11783920#post11783920 target=_blank>Originally posted</a> by Fishbulb2
I believe you should have replaced the flow restrictor but this is easy to test for. Simply turn off your storage tank (if you have one) and measure the waste to good ratio. If it is less than 4:1, that is if you are flushing the membrane with less than 4 gallons of waste to each gallon of good, then you NEED to replace the restrictor. The waste water serves to flush the membrane and removes all of the TDS that is rejected by the membrane and sends it down the drain. As you go lower than the 4:1 ratio, the membrane begins to clog and will prematurely fail. Definitely measure this ratio and adjust for it accordingly.

FB

I have not tested this. IF I had a 90 resrictor and a 150 membrane, would I get better good/waste ratio? or would it be more waste? I do know that I get quite a bit more waste than good...obviously. I would guess 4 or 5 to 1. But that's just a guess. I'll look in to it tommorrow. I guess I have 2 questions.

1. If someone had say 6:1 ratio, would they need a bigger flow or less flow?

2. Where to find a flow restricor rated for 150 GPD? The biggest I found was 100.

Thanks so much for you expertice! You are very kind to help all of us out with your wisdom.

 

[Fishbulb2]

<a href=showthread.php?s=&postid=11784023#post11784023 target=_blank>Originally posted</a> by '06Siguy
I have not tested this. IF I had a 90 resrictor and a 150 membrane, would I get better good/waste ratio? or would it be more waste? I do know that I get quite a bit more waste than good...obviously. I would guess 4 or 5 to 1. But that's just a guess. I'll look in to it tommorrow. I guess I have 2 questions.

1. If someone had say 6:1 ratio, would they need a bigger flow or less flow?

2. Where to find a flow restricor rated for 150 GPD? The biggest I found was 100.

Thanks so much for you expertice! You are very kind to help all of us out with your wisdom.

Your 90 restrictor should not be allowing as much waste water to drain and thus you should have less than a 4:1 ratio. This would be a bad situation as over time you will get clogging and failing of your membrane. I am not 100% certain on the relationship between the restrictors across GPD ratings so please check it to verify for both of us. But that I what I believe you will see.

1. If you have greater than 4:1 waste to good ratio, then that is great for you membrane in that you will be flushing more brine waste down the drain and reducing the risk of membrane failure. The two drawbacks are that you are using more water to make each gallon of RO water and that at the extreme end of the spectrum (a very high waste to good ratio) you may see a drop in the pressure measured at the membrane housing. This is what I see when I temporarily by-pass my restrictor (by using the flush valve). The pressure at the membrane drops very fast. This is of course a bit extreme but if you were fighting low pressure to being with, then I would not set the waste ratio high than 4:1. If you are worried about being able to precisely set the ratio using the capillary restrictor, don't worry about getting it perfect. Just get it as close to 4:1 while staying above. It's fine if it's a little higher but you should be able to get it close. Just don't go under.

For a flow restrictor for your 150GPD membrane go here:

http://www.buckeyefieldsupply.com/showproducts.asp?Sub=109&showspecials=109

BFS-272

Let us know how it goes.

FB

 

['06Siguy]

FB,

I just measured my waste/good ratio and I'm sad to report it came back at 3.7:1 and this is at 57 degrees. I'm pretty sure I want a new resrictor, like you said. The only problem is...I don't know what the restriction is at now, so I don't know how much higher to go. Like I said before, the restricor says "organic 800". I have no idea if that means anything about restriction, but I would guess it does. Do you know? If not, maybe I'll just order a few different sizes and just see what works best.

 

[Fishbulb2]

I believe that is for a 100GPD membrane. The only restrictor I have seen is from buckeyefieldsupply. Here, halfway down or so

http://www.buckeyefieldsupply.com/s...howspecials=109

BFS-272

check them out. The restrictor will be different from what you are using now. Instead of splicing it inline to your drain, you remove your current restrictor and insert the new one into the drain line. To do this disconnect the drain line from the membrane and insert the capillary restrictor in the end of the drain line closest to the membrane housing. Then you will need to recalculate the waste to good ratio and trim the capillary style restrictor until you get the proper ratio.

FB

 

['06Siguy]

I'm very sorry to say I don't know what you're saying. I understand the inline style...it's so very simple. But this capilary...I'm very confused. Something about trimming a line to increase/decrease flow? I'm a noob, and here it shows.

 

[Fishbulb2]

<a href=showthread.php?s=&postid=11784512#post11784512 target=_blank>Originally posted</a> by '06Siguy
I'm very sorry to say I don't know what you're saying. I understand the inline style...it's so very simple. But this capilary...I'm very confused. Something about trimming a line to increase/decrease flow? I'm a noob, and here it shows.

No problem. Have you looked at the link I posted to buckeyefieldsupply to see what the capillary restrictors look like? It is basically a long thin narrow tube that can literally be inserted into the drain line. So first you would start by removing your current flow restrictor that is an inline model designed for you old membrane. At this point you will now have no flow restriction at all.

To install the capillary restrictor you simply disconnect the drain line from the membrane housing and slip the very narrow capillary flow restrictor into the drain line. Since water now has to flow inside this narrow tube before eventually exiting into the regular drain line, a restriction is formed. Basically it is a tube within a tube. A thin capillary restrictor inside your drain line. Now, the exact resistance of the capillary style restrictor is directly dependent on it's length. So you can trim it to allow more water to exit the drain line. These types of restrictors are inexpensive and very very precise. I also have not seen inline style restrictors for 150 GPD membranes. But don't be intimidated by the capillary style restrictor. They are very easy to install. Just get one extra or so in case you make a mistake and trim it too thin. Trimming it to size will basically involve measuring the ratio, removing and trimming the restrictor, reinstalling the restrictor, and remeasuring the ratio to make sure it is ok. Repeat as many times as necessary.
FB

 

['06Siguy]

First of all, I must say I feel like I owe you something. You have been so helpfull! If there is anything I can do for you...let me know. I'd be happy to give you readings on this 150 GPD for your input if youd like. I don't know how else I could repay you for your kindness and helpfullness. If you think of something , let me know.

I think I understand the capilary style now. correct me if I'm wrong, but it seems to me that you'd take the 1/4 inch tube coming from the waste, and depending on the length of tubing inside that tube, will deturime the flow of waste. I hope it's 1/4 inch. cuz that's what I'm using. Like you said, you'd only use it if you removed the in-line one. Am I off here, or is that right? Because it is starting to make sence now.

 

[five.five-six]

I just placed an order with BuckeyeFieldSupply.com Russ spent a bunch of time with me and looks like he hooked me up! I will let you all know when it arrives

 

[Fishbulb2]

<a href=showthread.php?s=&postid=11785162#post11785162 target=_blank>Originally posted</a> by five.five-six
I just placed an order with BuckeyeFieldSupply.com Russ spent a bunch of time with me and looks like he hooked me up! I will let you all know when it arrives

Great! Russ at Buckeye is great. You will very pleased no longer standing in the rain.

FB

 

[Fishbulb2]

<a href=showthread.php?s=&postid=11784675#post11784675 target=_blank>Originally posted</a> by '06Siguy
I think I understand the capilary style now. correct me if I'm wrong, but it seems to me that you'd take the 1/4 inch tube coming from the waste, and depending on the length of tubing inside that tube, will deturime the flow of waste. I hope it's 1/4 inch. cuz that's what I'm using. Like you said, you'd only use it if you removed the in-line one. Am I off here, or is that right? Because it is starting to make sence now.

Sounds like you've got it. Capillary restrictors will insert into standard 1/4 inch tubing. You will not have to replace your tubing at all. Just not, that if you look inside your drain line now, you will not have a capillary restrictor already installed, since your unit came with an inline restrictor for a lower GPD membrane.

Yes, let us know how your membrane works out. Who wouldn't want 150GDP if the rejection rates are same? Keep us posted.

FB

 

[ZippyBoy]

Alrighty, I've reading this thread (and the RO/DI FAQ) with great interest (going to finally replace my Tap Water Filter). Been reading all of the suggested websites. The one that seemed to make the most sense was the "Recommended Filter Array" as proposed on the Air, Water, Ice site.

Theoretically, having a waterfall tightening of filter screens makes sense.....

Do you water experts have any comments on that theory?

Second question...... The system that would seem to function the "best" would have a:
1. sediment filter
2. carbon block #1
3. carbon block #2
4. TFS membrane
5. D.I. resin chamber

Do I have the concept right here?


nice adds include: inline TDS meter, integrated water pressure gauge, RO split for drinking water, some type of auto-shutoff valve?

Lastly, if I am only going to use the system for tank water (and I cannot use a saddle valve hook up), I'm assuming that some type of connector that sits between the incoming water supply and the kitchen sink faucet is preferable to a screw in the faucet outlet type of connection....correct?

 

[AZDesertRat]

Two carbons really are not needed if at least one of them is a 0.5 or 0.6 micron Matrix Chlorine Guzzler.
If you have normal low sediment or particulate free tap water I would recommend a 1 micron or less prefilter, I use a 0.2 micron absolute rated pleated prefilter myself with 10x the surface area so even if I did have sediment it will still last longer and filter better. Follow that with a Chlorine Guzzler and a good RO membrane and a vertical DI filter.

I would pass on the inline TDS meter as they are not as accurate and should be used as a rough guide only, get a handheld instead. Get the inline pressure gauge, RO bypass valve and if you plan on filling a reservoir or pressure tank get the Autoshutoff valve.

An adapter to hook to the cold water supply is prefferable to a faucet adapter if you have access to under the sink. There are several options that can be installed without doing any permanent damage to the water line.


As a treatment plant operator the coarser to finer made sense to me too until I plugged the more expensive downstream carbon blocks with the stuff the prefilter passed on. I now subscribe to the get as much out at the head of the process as possible train of though so the finer stuff never reaches the membrane or carbon block.

 

[ZippyBoy]

Thank you very much...

 

[kmcneele]

I am looking to purchase an RO/DI unit. I just checked the info from my water company, and the chloramines in my water measure 0.04ppm. At this level, will I need a 5 stage unit (with 2 carbon filters) or will a 4 stage unit be ok? I am looking at these 2 units specifically:

http://www.buckeyefieldsupply.com/showproducts.asp?Category=168&Sub=166

http://www.airwaterice.com/product/1TYPHOON/Typhoon_5_stage_RODI_Reefkeeper_75_GPD.html

Thanks for all of the helpful info!
Katie

 

[Fishbulb2]

Hello Katie,
You chloramines level appear quite low to me but Russ at BFS and AWI will have more experience with those levels. For reference, here in San Diego, our last water report showed that chloramine levels were an average of 2.15ppm. So that is a lot higher than yours. Some people here do get by just fine with a single carbon block, such as the one used on the Spectrapure Maxcap. Since a lot of units already come with two carbon blocks I just simply urge you to keep using them if you live in an area with high chloramine levels. In your case, I suspect one carbon block would work fine but if you do go with the airwaterice unit, just keep using the two carbon blocks and rotate them out as I described above is cost is an issue. Also, if you do go with the AWI unit, get the 1 um sediment filter and two .5 um carbon blocks instead of their default 10 um sediment and 5 micron carbon.

FB

 

[kmcneele]

How is it determined whether (and which) filters need to be replaced? I thought I read somewhere about looking at pressure drops across the filters to determine if they are clogged. Does this mean that I should have a pressure gauge before the sediment filter and one before the RO filter? Or should gauges be fit in between all of the filters?

Katie

 

[AZDesertRat]

Pressure drop is a good indication. In most cases it is recommended you replace the prefilter and carbon block at 6 month intervals and unless you have a high sediment or silt loading in your tap water you may never see a pressure drop.
The reasons to change at 6 month intervals are one so you change before experiencing a drop in pressure, two so you can disinfect the housings while you have it apart and three so you do not exhaust the carbon and it loses its ability to adsorb chlorine which can damage the RO membrane.

Personally I do have two pressure gauges, one on the incoming tap water line and one after the filter array. Most good reef quality systems come with inline pressure gauge after the filters which is good except most municipal water systems don't have rock solid pressure year round so what appears to be clogged filters could just be higher water demands or seasonal pressure changes.

For the membrane you change it when you see either a drop in output flows or a decline in water quality. They usually last 3+ years or more if you keep up with the filter replacements, disinfection routine and use good quality filters.

The DI resin should be changed when you regularly see anything other than 0 TDS.

 

[Fishbulb2]

<a href=showthread.php?s=&postid=11792120#post11792120 target=_blank>Originally posted</a> by kmcneele
How is it determined whether (and which) filters need to be replaced? I thought I read somewhere about looking at pressure drops across the filters to determine if they are clogged. Does this mean that I should have a pressure gauge before the sediment filter and one before the RO filter? Or should gauges be fit in between all of the filters?

Katie

Hello again,
You are exactly correct in your understanding of pressure drops and sediment filter replacements.

Technically you can test and measure when each component of the system needs to be replaced.

The sediment filter: To test the status of the sediment filter, you should measure the pressure before and after the sediment filter and replace it once it starts to clog. More commonly, people will only have one pressure gauge just before the membrane housing to test for clogging in both the sediment and carbon filter. In practice though, I wouldn't worry too much about measuring the pressure drop unless you suspect you have a particularly high sediment load and are clogging your filters often. Under normal operation conditions just change your sediment every 6 months.

The carbon block. To test whether the carbon block needs replacing, you can can test it for clogging using the pressure gauge as described above and test it for chlorine break through with a chlorine test kit. Test the waste water line for chlorine. If you detect chlorine in the waste water line, then the carbon block is not removing it all and your membrane is being exposed to chlorine. In practice, just replace this filter every 6 months and ignore the chlorine test kit unless you have reason to believe chlorine is getting through.

Membrane. Replace the membrane once the rejection rate drops to an unacceptable level. A rough guide line might be around 94% or lower and you may want to replace it even earlier if you live in a high tds area.

DI resin. I would recommend replacing your resin once it consistently reads above 1 ppm. If brand new resin still reads 1 ppm then perhaps your meter is not well calibrated but basically once you get any rise in tds, you should consider replacing the resin.

HTH,
FB

 

['06Siguy]

Hello again,
My membrane came with a new Fastflush. And, opon further review, I figured that it was also a new flow regulator. It is. I installed it and checked the ratio. I was going at 7.5:1. I thought that was a little too much waste. Does the waste/good ratio depend on water temp? My temp is at 57. So, I would assume I would get less good water. Should I resrict it more to achieve th 4:1, or just leave it at 7.5:1?

I did like you said ant picked up a 100 GPD capillary style. I'm testing the ratio on that right now.

 

[AZDesertRat]

Yes the waste increases with colder water. If the flow restrictor is adjustable set it as close to 4:1 as you can for now and monitor it closer to summer when water temperatures may rise as it may need adjusting thne to get it back up to 4:1.