Ro/di problems - Am i missing something here?

[Anonymous]

[I recently setup my RO/DI but Im really disappointed in the water output. I purchased it off of Ebay. it is a 6 stage and came with a storage container. My water pressure is good and it seems as though the system is setup correctly but I am getting nothing more then a tiny amount of water out of it. If anyone can give me some tips or hints on what I might be doing wrong I would really appreciate it.

Thanks

If pics are needed I would be happy to take some.]

 

[Amanda]

[What size membrane is it? The output usually is pretty slow, mine will fill the 3g storage tank in a couple of hours.]

 

[Anonymous]

[The membrane is a 100GPD...Maybe Im asking for too much from it in the way of output. I knew they were slow but not this slow...]

 

[russelldubois]

[my 100 gpd unit fills a 5 gal container in about 45-55 minutes.
If the incoming water is very cold the time is quite a bit longer. The units are slow but definately worth the wait.

russ]

 

[Anonymous]

[Russ what type of system do you have??

Is there a way to set these things up wrong to where the output would be slowed?]

 

[russelldubois]

[I have the system that Marc sells on his site. This is my first RO/DI so I am not the best to ask if it set up wrong. I would try to post a pic of the unit and ask the masses.]

 

[Nautilus]

[Get a 5 gallon bucket and time it. If it take 45 minutes to fill it to the outside line then it is working fine.

If you have a flush system then it maybe set wrong.

You need a TDS meter to tell you what the output is and this will tell you if you are going through the membrane and DI filter.
Ask the guy you bought it from and he would know best.]

 

[melev]

[There are only three things to consider:

PSI (70)
TDS (under 200)
Temperature (77F)

* numbers in parenthesis are the ideal

If your PSI is 40, your output will be slower. The higher the TDS, the more pollutants your unit needs to filter out. And the colder the water, the slower your unit will produce water.

With my source water, in the summer my unit produces 5g in 60 minutes. In the winter, it takes 85 minutes to make the same amount of water.

If you'll go to my site and click on the RO/DI link, you can read up on a solution to speed up the output when the source water is colder.]

 

[Anonymous]

[Where locally can I pick up a TDS meter as well as a pump if I need one?? I know Lowes has neither...]

 

[kwl1763]

[In this weather you will be lucky to get 75GPD.

In breaking this down that is roughly 3G per hour.

Breaking down further it will take ~20 minutes to fill a milk jug. That is a trickle. Barely over a fast drip!

So you may have a problem or it may just be your expectations were to high. How much flow are you getting?]

 

[Nautilus]

[Sorry I will disagree with TDS under 200.
More water that is city water is 168 to 300 or there abouts in our area. 500 TDS is considered toxic.

You want to shoot for 0 TDS with new filters, and that is easy to do if you have a DI filter attached.

You don't want to use warm water as this will open up the holes in the Membrane and let the "evil doers" pass through. And it will also speed up the DI filter replacement.

Since this is a 100 GPH unit it should be 5 gallons or so an hour. Cooler water is best and your rejection rates are better.
I use the coldest water I can from the tap and never had an issue. If the out put is fluctuating then the water temp may be to warm. Cooler water is better output and you should see 0 TDS.

70 to 80 psi is great.
Online TDS $24 http://airwaterice.com/tds_meter1.htm]

 

[Anonymous]

[So lets say my pressure is low..What is the next step? I have seen pumps that actually use electricity and I have also seen pumps that use the waste water to run the pump. Does anyone have any reccomendations on what to get???]

 

[melev]

@Nautilus wrote:

[I was referring to source water at 200 TDS or lower. Obviously the whole reason we have RO/DI units is to have 0 TDS.

Colder water reduces membrane output. They are rated at 77F. Lower water temperatures slows production. If you warm the water to 76F as directed on my site, you'll get the optimum flow your unit can produce.]

 

[melev]

@96p993 wrote:

[You can buy a booster pump to bring your PSI up. Be sure the one you buy is rated for a 100gpd unit.

But before you do that, get a $7 gauge at Home Depot to determine your current PSI, and also unscrew the tubing going in your unit and see how quickly the water is coming out of it. It would be best to rule out any obvious problems before throwing more money at it.]

 

[Bustedup211]

[ I purchased a waterandice 75 gpd 5 stage3 wks ago and can produce 5 gallons with a 0 tds through the di and 6 tds through the ro in about an hour. Granted my unit is new. It does have back flush capability and if you do not have the valve that operates the back flush you will discharge you ro water before it get to the di filter. Might want to check there. :idea:]

 

[Nautilus]

[

Marc I was confused because you said numbers in parenthesis are ideal. The ideal TDS is 0 for sure.

The one problem I see from doing this is if you are not getting the water from the cold water line and have some kind of connection where you can adjust the temperature going to the input of the RO/DI unit, then you are pulling water from the hot water heater which we all know has alot of added minerals and sediment, which is an added risk and filter would need to be changed more often.

I have never tested this but maybe I should.
I use the coldest water I can, at 82 psi's and produce 5 gallons every 45 minutes to 1 hour with no problems. Last time I checked the temp it was 72 degrees.

The whole purpose is to keep the holes in the membrane as small as possible to reject as many harmful metals and chemicals as possible. The warmer the water the more the membrane lets through. I am happy with 0 TDS and when I see 3 to 4 on the TDS meter I change everything but the Membrane.]

 

[HSLee]

[if you suspect incoming water pressure to be the issue;
1) measure incoming pressure to the whole water unit (before stage1). It should be somewhere between 60 and 80 psi.
2) measure water pressure going into the RO membrane stage. You may have to splice a tee union into the filtration unit to install a pressure gauge. Water pressure there should still be >60psi. If the reading is lower, your prior filter stages may be spent, clogged. It is common for folks to keep a pressure gauge right before the RO unit to help monitor the life of the prior stages (sediment and carbon filter elements).]

 

[melev]

[@Nautilus wrote:

Marc I was confused because you said numbers in parenthesis are ideal. The ideal TDS is 0 for sure.

The one problem I see from doing this is if you are not getting the water from the cold water line and have some kind of connection where you can adjust the temperature going to the input of the RO/DI unit, then you are pulling water from the hot water heater which we all know has alot of added minerals and sediment, which is an added risk and filter would need to be changed more often.

I have never tested this but maybe I should.
I use the coldest water I can, at 82 psi's and produce 5 gallons every 45 minutes to 1 hour with no problems. Last time I checked the temp it was 72 degrees.

The whole purpose is to keep the holes in the membrane as small as possible to reject as many harmful metals and chemicals as possible. The warmer the water the more the membrane lets through. I am happy with 0 TDS and when I see 3 to 4 on the TDS meter I change everything but the Membrane."]
I was referring to the ideal SOURCE water. I must not have posted that clearly enough.

And I'm not recommending anyone use water from the hot water side. That is why I referred the reader to my site. Here's the exerpt:

Replace the tubing that leads from your cold water pipe to the unit with a 25' long piece. Coil as much of that tubing inside a 5 gallon bucket and fill the bucket up with water so the coils are submerged. Put an aquarium heater in the bucket and set it to 78° F. The heater will keep the bucket water at that temperature, and that water will warm up the water traveling through the tubing to your RO/DI unit. Production rates will jump back to normal.
]

 

[waterbeing]

[I have 2 - 100 GPD membranes in parallel on a 5 Stage unit and normally fill a 5 gallon container in about 40 minutes. I also have water at the kitchen sink and running through my refrigerator ice maker that are powered thru the same unit. The unit has 2 TDS meters (each with 2 points of measure) giving 4 metering points and I normally start with city water about 300-320. After all filtering it normally runs 2-5ppm and sometimes up to 10. I also use a permeate pump (http://www.aquariumwaterfilters.com/RODI/water_pumps.html)
to help with distance and pressure, but no input/citywater side pump. I've been very pleased with performance and output for fishies and us. ]