DI life expectancy

[duc]

So I break down and buy an RO/DI and after 100-120 gallons my DI is shot.
Does this sound freaky fast or is it just me?
Seller (sponsor) says it is not unheard of but seems a bit fast and is "willing to sell me a new one".
Is it just me or was it bad to begin with and I shouldn't have to buy a new one?
Anyone have a local source for the refill material (bag of DI not cartridge)?
Clif

For those curious types:
City water
Water softener
225ppm from tap

[alton]

I had the same problem with my water. It did not matter which brand I used. I quit using the DI cartridge because I couldn't afford it.

[discuspro]

Do you have the DI in a clear canister? That may help to see the color change rate, if you have color changing resin. Check your TDS right after the RO membrane, it may be bad and over working the DI resin.

What is the 225ppm? Calcium? Any way to not have softened water go to you ro system?

[Marlin]

Is it bad to feed your RO/DI system from a soft water source?

[thedude]

Just for reference, I use a 50 GPD RO filter from Aqua FX with Dual DI cartridges on it. When pressurized, the RO TDS is about 4-5 sometimes as low as 1. I've been using it for close to 8 months and haven't used 1/3 of the first DI cartridge. It sounds like something is wrong before the DI section and you're flooding the DI with dissolved solids. Tell us a little more about the water system before the DI.

John

[duc]

Do you have the DI in a clear canister? That may help to see the color change rate, if you have color changing resin. Check your TDS right after the RO membrane, it may be bad and over working the DI resin.

What is the 225ppm? Calcium? Any way to not have softened water go to you ro system?
The 225ppm is the reading I get from tap water using my TDS meter.
The only way would be to turn the soft water off for the whole house while making water. I was told by several (including seller) it would prolong the life of everything using soft water.
Clif

[duc]

Just for reference, I use a 50 GPD RO filter from Aqua FX with Dual DI cartridges on it. When pressurized, the RO TDS is about 4-5 sometimes as low as 1. I've been using it for close to 8 months and haven't used 1/3 of the first DI cartridge. It sounds like something is wrong before the DI section and you're flooding the DI with dissolved solids. Tell us a little more about the water system before the DI.

John
This is the unit I am using:
http://www.purelyh2o.com/cart.php?target=product&product_id=89&category_id= 1
What do you mean by, "Tell us a little more about the water system before the DI"?
Clif

[TexasTodd]

I use get about 300g out of a DI cartridge.

If you have your RO/DI hooked up to auto top off it eats the DI MUCH faster as every time it fires up to make more water the first pint or so of water is very high in particulates.

Todd

[thedude]

Yeah after looking at the link, I'd point my finger directly at feeding your until soft water. As todd mentioned as well, RO units are not good with continual on/off applications. It's best to fill a reservoir, let it drain completely, then refill.

[matt]

If you have the auto top off from purely H20, it includes a pressure switch that supposedly prevents the problems of constant off/on to the R.O. membrane; I believe it leaves the membrane pressurized so that the initial flow through does not pass on high TDS to the D.I. cartridge.

If you did not flush your R.O. membrane when it was new, the first 10 gallons or so through the membrane probably really ate up the D.I. resin; apparently when the membrane is new it contains a biofilm which should be flushed out before passing water through the D.I. I learned this on the phone talking with Bryan from purelyH20 while I was figuring out why my new filter was spewing water out the waste line like a fire hydrant; that's the flush kit.

Also, you might have the refillable D.I. cartridge which makes it much cheaper to replace; you just buy a bag of resin and refill it when it's exhausted. You might give Bryan a call and ask him about that, about the flush, and especially about the water softener. Somewhere I seem to have read that using a water softener really is hard on an R.O./D.I. unit.

[Bill S]

I'm not sure why a water softener would be hard on an RO/DI unit. I've had my first one for about a year, and I just replaced the DI resin. It's been hooked up to my icemaker too - classic on/off cycling. I still had nearly 0 tds when I replaced it. I pay $10 a bag for the resin. Also remember that SOME manufacturers (Coralife) don't use the expensive (correct) resin.

[duc]

OK so it looks like I did everything right and that maybe the softener is shortening the life of the DI.

bstreep where is it you purchase you resin from? I can find it for $15 on-line but as you know $10 local is better :D
Clif

[discuspro]

I know softeners exchange Ca and Mg ions for Na and K. Not sure if the softener is causing all the trouble but I do remember living in a house with a water softener and finding all of the glasses that I drank from became really scratchy and rough feeling after a few years of washing. Pretty sure Na is filtered easily by a good working membrane. Check this article it also has a link telling how to recharge DI resin, but it might not be that easy unless you know what solutions they are using.:

http://www.reefkeeping.com/issues/2005-05/rhf/index.php

This might be arguable but I just found this quote from this link, "If you have especially hard water, you might consider running it through a water softener before the RO/DI filter. That process removes calcium and magnesium by swapping sodium for them. While aquarists are not generally worried about calcium and magnesium in their source water, they can foul RO membranes by forming calcium and magnesium carbonate precipitates inside it. That precipitation will reduce flow and eventually make the membrane unusable."

Maybe I should retract my first statement, but all of this just seems weird.

Also, found this quote, which I've always wondered about myself when it comes to silicate, "It may also be desirable to have two DI cartridges in series if there is a lot of silica or other easily penetrating problem ions in the RO permeate."

[Bill S]

The reason why you have etched glasses is that you are using too much detergent. The recommendation with a water softener is 1/4 to 1/2 the normal amount.

I buy mine online from www.aquasafe.com.

[jim1000]

Check to see if your water system uses cloren(sp), or clorimen(sp) which san antonio did some months ago. T normal carbon filters does not work for this, and eats up di cartriges. Purly h2o carries this carbon, call and talk to the owner.

Jim

[duc]

Brian (the owner) has been more than helpful I was just feeling around to see if I was the only person who has had such a short life. He said he sells medical grade which last longer, main difference is it doesn't chg colors so I have to use a TDS meter (which I do) to monitor it.

At what ppm should I quit using my water? Is 8ppm OK, borderline, or bad water?
Clif

[matt]

8ppm TDS is pretty low; I wouldn't worry about using that water at all. I used to have a Kent R.O./D.I. filter and could never get TDS below 10ppm. I've produced about 30 gallons so far with my purelyH20 filter and the D.I. has changed color on about 2".

[duc]

8ppm TDS is pretty low; I wouldn't worry about using that water at all. I used to have a Kent R.O./D.I. filter and could never get TDS below 10ppm. I've produced about 30 gallons so far with my purelyH20 filter and the D.I. has changed color on about 2".
That sounds just like mine 2" real fast then the whole thing withing 70-80 gal's more and now I have lots of white after a total of 120-130ish. Interesting I wonder if he had a bad batch since two of us have the same results or if this is normal, I am also curious how yours will be doing in 90 more.
Clif