Why am I burning through DI filters?

[NedFlounders]

Seems I have to replace the DI cartridge only after about 200 gallons. It begins to turn orange after the first use.

With a new filter, TDS are about 140ppm going in and 0 going out.

After about 200 gallons, the output is about 3-7ppm.

Pressure is steady at 75psi. What's the dealio?

 

[gone fishin]

I noticed when I set my ATO up so it does not short cycle my RO/DI, the DI life extended greatly.

 

[Dogshowgrl]

What is the water that is incoming? Well? City water? Your local area?

 

[chucko]

maybe you have Chloramines?

 

[NedFlounders]

It's city water (Seminole County in Orlando).

 

[chucko]

According to http://www.seminolecountyfl.gov/core/fileparse.php/3234/urlt/2014-Water-Quality-Report.pdf you probably do have chloramine in your water.

 

[NedFlounders]

According to http://www.seminolecountyfl.gov/core/fileparse.php/3234/urlt/2014-Water-Quality-Report.pdf you probably do have chloramine in your water.

chemistry :facepalm:

hmm, so if the chloramine is what is causing my DI filters to get used up so quickly, is there a fix? Perhaps another stage in the RO/DI system?

 

[gone fishin]

From what I have read in passing, I don't have chloramines, there are carbon blocks designed for chloramines and chloramines can damage the RO membrane. Please verify that info.

 

[shifty51008]

A good carbon filter will remove the chloramine

What is your tds of tap, and ro? What is the water pressure? Do you make water alot at a time or just small batches? Do you put the 1st few gal's down the drain of ro water before letting it run through the di?

 

[water is wet]

I believe this happens because of co2 being abundant in your water supply. At least that was the answer I came up with after moving and going from making thousands of gallons before needing replaced to less than the 300 gallons per day the unit is rated for.

 

[NedFlounders]

ShiftY:

With a new filter, TDS are about 140ppm going in and 0 going out.

After about 200 gallons, the output is about 3-7ppm.

Pressure is steady at 75psi.

I try to make 50 gallons at a time. Not sure how I'd let the RO run w/o going through the DI? It's a 4 stage AquaFX.

 

[shifty51008]

Co2 issues only come up when running off well water.

 

[shifty51008]

Whats the tds of the ro water, after the membrane but before the di?

You would have to add a T line before the di with a ball valve, this way you can drain the 1st few gal's of water that have high tds. When i 1st turn my bypass on the tds is around 20-30, sometimes much higher. I will drain the water till the tds gets down to around 3-4ppm then let the water go to the di. If i let tge water with 30ppm go to the di it will kill it fast with that high of tds. A di canister can only remove so much tds before it's shot so the less ammount of tds going in will make it last longer.

Hope that makes sence

 

[NedFlounders]

Yes Shifty, that makes perfect sense. Thank you!

Just got off the phone with my LFS, they seem to think it's some kind of backflow valve that isn't working right and isnt' flushing the DI cartridge (or something to that effect). Good news is I learned AquaFX is only about 5 miles from my house!

 

[shifty51008]

I think he means flushing the membrane, di doesnt need flushed, but flushing the membrane helps keep it clean and flushing when starting the unit will help with the high tds reading's youll get at startup but still good to flush the 1st gal or so or until the tds drops before going to the di.

Hopefully aquafx can help you out also, nice they are that close.

Good luck

 

[NedFlounders]

So after talking to AquaFX, they said it sounds like chloramine. (good job for those above that mentioned it). They said it most likely destroyed my membrane and is causing the DI filter to do all the work. So now I have a "chloramine blaster" en route as well as a new RO membrane. Good grief this hobby is expensive lol :eek2:

 

[shifty51008]

Lol, that is why i asked what the tds of the ro water was. You can figure out the rejection rate of the membrane with the tds of tap and ro water and see if your membrane is good or not.

A good thing to keep in mind is to replace the sediment filters when they start turning brown or every 6 months which ever comes first and change the carbon every 4-6 months depending on how much water you use. Change the membrane when the rejection rate starts to drop to 95% or less and change the di when tds reads 1ppm.

Good luck.

 

[Fish Keeper82]

Whats the tds of the ro water, after the membrane but before the di?

You would have to add a T line before the di with a ball valve, this way you can drain the 1st few gal's of water that have high tds. When i 1st turn my bypass on the tds is around 20-30, sometimes much higher. I will drain the water till the tds gets down to around 3-4ppm then let the water go to the di. If i let tge water with 30ppm go to the di it will kill it fast with that high of tds. A di canister can only remove so much tds before it's shot so the less ammount of tds going in will make it last longer.

Hope that makes sence

The above statement would be my guess known as "TDS Creep" if your ppm is 3-7ppm after DI is exhausted i belive your menbrane is still good. I have the same membrane since 2007 and have 4ppm coming out after my ro membrane still to this day. When i initially turn on my sytem it shoot upwards of 70 ppm for about 15 seconds and slowly comes down to 4-6ppm in 4 minutes time.
I think if chloramines would have destroyed your ro membrane your numbers would be much higher than 3-7ppm. Chloramines could be a factor and good thing your getting the filter but just my opinion your membrane is more than likely still good i wouldn't change it just yet. 7ppm is a 95 % rejection rate and thats your high end the low ppm is about 98% rejection rate which is pretty normal.
Make shure you are testing TDS after a couple of mins run time at least like 10 mins to get the TDS creep out of the equation.