RO/DI is already out 100 gallons later?

[mitsu_matt]

Well I just got a brand new RO/DI unit from Vertex, connected it and was off and running. Two weeks later and ONLY two water changes later my TDS meter is reading 7PPM and it looks like the DI resin is almost exhausted. I only made less than 100 gallons, ***!. Has anyone else had this problem and does this seem correct?

 

[karsseboom]

what was the water temp that was going through the filter?

 

[jduck]

What is the water pressure? What is the TDS before membrane?

 

[mitsu_matt]

Not sure the water temp, cold but not ice cold.
My water pressure is anywhere between 30 and 50, but the RO/DI has a pump and it keeps the pressure high.
TDS before membrane is between 500 and 700.

 

[Jukas]

Your TDS levels probably have something to do with it, however that still seems fast to exhaust a DI resin.

Average city water is between 140-400ppm TDS. EPA lists maximum acceptable contamination levels at 500ppm.

 

[jduck]

That is a really high level pre membrane. Have you measured what is is coming out of membrane before di? Another way to improve is put a coil of tubing in a 5gal bucket with a heater and heat up the water before it goes into membrane

 

[FearTheTerps]

it very well could have exhausted it that fast with such a high TDS. Is it an in-line or vertical cartridge? Usually the vertical have a higher capacity.

Using worse case scenarios, 700ppm source, membrane reduce 95%, and using a in-line membrane with a capacity of 3400 ppm.


The membrane would reduce the TDS down to 35ppm that goes into your DI resin.
700ppm * 5% = 35 ppm

3400 ppm divided by 35ppm = 97 gallons

 

[bamf25]

I just ran anough water through my new ro/di to fill a 140g system. It used up about 15% of my di filter. I live in the Northeast so the water is fairly cold right now. I was even a little bit surprised that it use up that much to be honest. On average the water coming into the di has about 5 ppm for tds, but when you start the unit you will get a spike in the tds coming into the unit for the first 1 minute or so, while the ro gets reved up. I saw it hit 60ish during the first on period. So if you are doing alot of on/off use, you could use the resin up faster. By fears calculation my tds is my water supply is in the 100 to 150 range.

 

[JoeRonda]

That is a high source water tds. I like to put the "in" sensor before the di canister so i can see what the reading is after the ro membrane, and put the
"out" sensor in the product water hose so I can see what the reading is after the di resin. That way you can tell when your ro membrane is getting exhausted. Also you should have gotten more than 100 gal of product water because even if the ro membrane becomes exhausted, the di resin should'nt let any impurities through until it becomes exhausted.

 

[bamf25]

He said the unit was brand new, so the ro mebranes should have close to 3 years left on them.

 

[Sk8r]

Ow. You might prefilter it with a Sears inline drinking water filter to see if it can knock some of that out of the water before it gets to your ro/di. You MIGHT want to install a drinking water filter on your icemaker and house drinking water.

 

[JoeRonda]

He said the unit was brand new, so the ro mebranes should have close to 3 years left on them.

That depends on the amount of impurites of his source water. The ro membrane will last anywhere from 3yrs. best case senario, to 6mo. worst case senario. And at $50-$80 for a replacement membrane, I would take Sk8r's advice.

 

[mitsu_matt]

Yea, I have a whole house filter and a filter on each of my icemakers. As stated the RO/DI was brand new so I doubt the membrane was bad.

I do have a TDS meter on my drinking RO system in the kitchen and its reading 803 today! And the vertex RO/DI has a built in TDS meter and backwash. I really thought the DI resin would last longer and wanted to see if maybe it was a problem with something else. I guess I am up a river with out a paddle on this one!

 

[JoeRonda]

Does your DI Resin still look grey,green? Or is it all brown?

 

[karsseboom]

wow my city water on the tds in 25....

 

[mitsu_matt]

Does your DI Resin still look grey,green? Or is it all brown?

Top down, its 8" light brown last two inches are the original darker brown.

 

[ragingreefer]

Did you flush all the filters one at a time with out the next filter hooked up. I did not do this with mine when it was new and it wiped out the membrane and di pretty quick. After that costly mistake I flush each step of the filter before I hook up the next. If you check with a tds meter it should drop after each filter before going to the next step.

 

[travis32]

I'm surprised so many people are trying to troubleshoot this. There is nothing wrong.. My in water to my RO ranges between 750 and 950 TDS. My out ranges between 35 and 50 TDS to my RODI and my DI brings it down to 0.

I get approximately 100- 150 gallons out a single DI Resin fill. I have the vertical DI resin, and I'm not sure what temp would have to do with how long the DI resin lasts? That makes no sense to me. The temp determines the speed at which the water flows through the RO. But, should not determin the rate at which Deionization occurs. Once the water is deionized I can't see how it would be "more de ionized" because it's flowing slower. 0 ions is 0 ions.

 

[fatdaddy]

I'd agree with Travis. I have terrible city well water and my RO knocks it down to 7ppm which I consider excellent.

How big is your DI cartridge? If it's one of those little ones, I'd say your doing good. I'd buy one of these:

I wait for one to exhaust and then refill and flip. The DI they sell usually fills up one and a little more, so I just put it in the other.

There are situations that will exhaust DI extra fast such as CO2 in the water. I think there are others. If you're still concerned, I'd google for it.

 

[FearTheTerps]

Temperature only effects the RO membrane. A low temp will effect the waste to product ratio of the membrane(as can pressure). Where a normal rate is about 4:1 ( 4 parts waste to 1 part product), a cold water source may a rate as high as 7:1. A high temperature source water can cause the membrane to be inefficient, lowering the reject rate. A normal reject rate is about 95%-98%, a high temp can cause the rate to drop to 90% or lower. A higher temp will also effect the lifespan of the membrane itself.


TO THE OP, I would get your water tested, I assume this is well water we are talking about. Like someone said earlier, the EPA has guidelines for what is considered to be fit for human consumption, its 450 ppm. TDS meters only test for total particles, those particles could be a combination of anything. I would get your water tested by a local water company so you can find out what is actually in your water. Some things in the water are fine to drink in high quantities, but others are not. Your RODI unit works the same way, some particles are easier for the membrane and the DI to process then certain other particles. If you find out what is in the water the water company may be able to provide you with prefilters that can take most of the bad stuff out before it goes to the RO unit.